|“||Yeah, join you. Right. Until you get bored of me and turn me into a Leosicle? Lady, nobody messes with my dragon and gets away with it. I can't believe I thought you were hot.||”|
Leo was born in Houston, Texas to mechanic Esperanza Valdez. When he was little, he had a babysitter named Tia Callida, whom later was discovered to be Hera in disguise. She was watching Leo because she knew of his destiny as one of the seven in the prophecy. She tried to "kill" him by putting him in an active fireplace and by letting him play with knives. She also tried to make him poke a rattlesnake, which he refused to do. This was done to help train Leo to be strong at a young age. He once drew a picture of a flying boat with a bronze dragon head as the masthead in crayon at the age of five and just as Leo was going to sign his name on the picture, it was blown away by the wind. Tia convinced him to use his abilities to start a fire to "warm these old bones," and he ended up burning his fingerprints into the table.
At the age of eight, Leo was visited by Gaea, the Earth goddess, whom intended to break his spirit, after being notified by Medea that he would have a part to play in her downfall. Horrified, Leo tried to use his pyrokinetic abilities as defense to save his mother and himself, but Gaea manipulated the fire, burning the mechanic shop. His mom died in the fire, and his Aunt Rosa turned his remaining family against him, thus forcing him to be sent to several foster homes.
The death of his mother haunted Leo for years. The emotional strain caused him to run away from multiple foster homes. After running away for the sixth time, Leo was sent to the Wilderness School, where he met Piper McLean, who unbeknownst to him, was a daughter of Aphrodite. When Hera switched Percy Jackson and Jason Grace, she manipulated the Mist so Leo would think Jason was his best friend, although they became real friends later on. He is said to be the only living son of Hephaestus that is able to generate fire.
Leo goes to the Wilderness School with Piper and Jason. He partners up to complete their assignment with Jason on their field trip to Grand Canyon. During the ride there, Jason says he does not remember anything and Leo thinks that he is playing a joke on him. When Gleeson Hedge, their coach, yells at them from the front of the bus, Leo says that he can not hear him, prompting Hedge to use his megaphone. When Hedge turns on the megaphone, it sounds like Darth Vader or shouts out phrases like "The cow says moo," something that Leo had done as a prank. He seems to be good friends with them at first and seems to know Piper very well, knowing who her dad is and being able to tell that she likes to fight her own battles when she is picked on by some of the mean girls on the trip. When they are walking across the sky-walk, a storm appears around them and Leo is the one that notices the storm is only in this area and nowhere else. As the storm begins to get really bad, most of the students run away back inside with the exception of Jason, Leo, Piper, Dylan, and Coach Hedge.
Dylan reveals himself to be a ventus, or a storm spirit, and attacks the others with the help of two other venti. Leo is thrown off the sky-walk and slams into one of the canyon walls. While Jason and Piper try to fight Dylan, Hedge takes off his disguise and shows the others that he is a satyr sent to protect Leo and Piper. He jumps over the side and manages to grab Leo, pulling him back up as Jason fights off the venti using his Imperial Gold sword, Ivlivs. Hedge manages to get Leo back onto the sky-walk, where Dylan tries to abduct him. At the last minute, Hedge intervenes and is abducted instead.
Annabeth Chase and Butch arrive and rescue them on a flying chariot, bringing the three demigods to Camp Half-Blood. While on the way back, Leo makes a few jokes about how Butch is a child of the rainbow goddess, Iris, and is one of the best campers with the pegasus. When Butch threatens to toss him off the flying chariot, Leo sarcastically back tracks saying that rainbows and ponies are very macho. Once arriving at camp, Leo is immediately claimed by his father, Hephaestus, and goes on a tour of the camp with Will Solace, a son of Apollo and head counselor of cabin seven, who brings him to Hephaestus' cabin. It is here that he meets Jake Mason, the current head of the cabin. Jake is in a full body cast after trying to stop the Bronze Dragon that has started going crazy and attacking the camp. He also explains that after Charles Beckendorf's death, the cabin has been under a curse that makes any creation of the cabin turn to junk. When Leo asks if anyone at the cabin can control fire, one of the members of Cabin 9, Nyssa, tells him that only a few people in history have ever had that power and it is considered a curse because it normally causes great destruction.
That night, at the campfire, Leo is very quiet until Rachel Elizabeth Dare gives out a quest to Jason. When Jason is about to pick which member will go with him and Nyssa volunteers herself, Leo stands up and claims that it is him that must go on the quest, offering that he also has an idea on the transportation problem. Jason says that if he can get them a way to fly, he can go with them. That night, Leo goes into the woods looking for the bronze dragon and stumbles upon a trap set up by Cabin 9 to capture it. The dragon appears in front of Leo, who is upset that the dragon does not have wings to fly. The dragon blasts him with fire, but Leo's body is unharmed because of his Pyrokinesis. After it falls into the trap, Leo takes the chance to find the control panel and fix some of the wiring inside it's head. After he fixes him up the best he can, the dragon asks Leo to climb on his back and takes him to Bunker 9 where he finds a magic toolbelt and a set of bronze wings for the dragon. He spends most of the night working on the dragon and appears in front of everyone the next morning saying he found Jason and Piper a ride, naming the dragon Festus meaning "happy" in Latin. When asked where he got the wings, he says he found them in the woods but does not mention the bunker. Jason keeps his promise, and chooses Leo as the last member of the three campers to go on their quest to save Hera.
They begin to fly to Quebec, Canada in order to talk to Boreas to find out where to find Hera. They meet the two sons of Boreas, Zethes and Calais. The brothers say that they can't land unless it's an emergency landing, so they trick them into letting them into Boreas' palace. Festus is not allowed in as he is a fire dragon, so Leo flips a switch and Festus turns into a suitcase (but still weighs the same, which is 60 million tons). When Khione, the snow goddess, comes down the stairs, Leo immediately falls in love with her as soon as he sees her, but she dislikes him because she can sense that he can summon fire (as Boreas' children can smell fire). He is not allowed to meet with Boreas as ice and fire would not be ideal in this situation. While his friends were gone, he has his clothes cleaned of the oil and dirt gathered on him from fixing Festus. Leo is upset that Jason and Piper made Khione mad because he was planning on making her his prom date, not knowing that she likes to collect demigods as ice statues. Jason later explains this to him, which Leo thanks him for.
After they leave, Festus is knocked out of the sky and crashes into an abandoned car factory while Leo was resting. Leo runs off to go and find where Festus landed, which turns out to be in a row of portable toilets. When he looks inside the dragon's head, it is shown the reason Festus crashed was because the wiring had frozen over, something that shouldn't of happened as it would of been too hot inside his head. While he is fixing the dragon, the face of Gaea appears in the snow, sludge, and dirt and tells him to walk away from his friends and let him die. He tosses one of the toilet lids at the face and the face disappears.
When he gets back to the factory, Jason and Piper have been captured by three cyclopes called Ma Gasket, Torque, and Sump. Piper sees Leo sneaking around and keeps the monsters talking while he creates a remote to control some heavy lifting machinery. When one of Ma's children leaves, he uses that moment to attack, taking out her son by tossing him through the roof and then crushing the other with a metal claw when he returns. Ma Gasket is also defeated when Leo uses his fire to break a chain, causing an engine to fall on top of her. When he goes to free Piper and the unconscious Jason, the dust of the cyclopes begin to reform. He rushes them back to Festus, hearing them reform inside the factory. Piper thinks that his fire powers are cool, but he still feels like they are a curse because he thinks that it was his fire that caused his mom's death. He also tells them that children of Hephaestus are only born with fire powers when bad things are about to happen, but Jason cheers him up by suggesting that they are born with those powers because that is when they are needed most.
When they arrive in Chicago, Leo takes a whistle out of his pocket and teaches Festus to come when he is called. After that, the group follows a group of storm spirits into the sewer system where they get some rest while Leo makes some food for the other two. They follow the wind into a shopping mall, which is owned and operated by Medea. They find that in Medea's mall, Coach Hedge and some venti are locked in cages. Medea begins to charmspeak the trio, but Piper is able to resist. Leo and Jason begin shopping for new clothes, potions, and soon forget the reason they were there in the first place. Medea soon turns Leo and Jason on each other and tries to force them to kill each other. Piper, trying to get them back to their senses, gets Medea to admit that she can see the future and told her patron about Leo being one of the seven, leading to the death of his mother. This is enough to break the spell over Leo and Jason, but Medea lets loose the Sun Dragons to fight them off while she escapes. He calls Festus who is able to fight off the other two dragons and the three fly off with Coach Hedge and the venti while the mall is destroyed thanks to Piper.
As they are flying, Leo falls asleep and has a dream of his father Hephaestus, who is using an old pirate radio broadcaster to speak to Leo without Zeus knowing. At first, Leo is very angry with him for not coming to see him sooner, but softens after seeing that his father acts the same way he does when he is nervous (fiddling with gears and small machines). His father tells him that the gods closed themselves off from their children because of Zeus' orders; partly because he felt that their children should respect them and he felt ashamed that the gods needed the help of mortals, and also because Zeus was worried that their activities on Earth were awakening Gaea. Not long after the dream starts, Zeus picks up on the dream and cuts the connection.
When Leo wakes up, Festus is crashing to the ground and he tells Jason to carry Piper away. Jason is unwilling to leave his friend, but does so anyway while Leo tries to reboot Festus. Once the dragon comes back online, it is already too late and the crash into the yard of a large house. Leo survives from the crash. When he comes to his senses, Festus is destroyed by the house's defense system (lasers) and Leo asks his father to bring his head back to Bunker 9 so he can reuse him, as that was Festus' final wish. Leo takes it very hard and thought it was his fault, leading Festus to his death. But soon, Jason said he couldn't do better, Festus was the best dragon he had ever seen.
The house turns out to belong to King Midas and his son Lityerses. At first, all seems to be going well until Midas turns Piper into gold and when he tries to fight him with his fire, he can't (the gold suppresses his powers). He is also turned to a gold statue, but is freed after Jason defeats Lityerses and washes off Leo and Piper in the river, which is freezing cold. Jason uses the storm spirits to fly them away from the house and after setting up camp, Leo makes tofu burgers for Piper and the newly freed Coach Hedge.
Not long after, they are attacked by a pack of wolves lead by Lycaon, the first werewolf. He says that their weapons will not work on him because he can only be hurt with silver, but Leo pulls some gasoline out of his belt and lights some of the wolves on fire, but it isn't enough to hold them back. He is only saved thanks to the timely arrival of the Hunters of Artemis that shoot the wolves with silver arrows. Leo falls in love with Thalia after only seeing her for a second and thinks that she is too hot to be Jason's sister, but doesn't tell him that. When the Hunters set up camp, a few hunters go to take care of Piper and Leo begins to follow them, only for Jason to ask him to stay as he begins talking to his sister. He learns about how he was separated from his sister and about Jason's mother, making him feel bad for Jason.
When Piper is fully healed, the group begin to travel to Aeolus' palace, but on the way up Leo asks why a wind spirit would need a bridge, to which Thalia says it is an anchor so that it doesn't fly away. Leo gets an idea from this about what Hera said about Jason being a bridge, and a bridge must connect to something. His mind begins to race so fast that his fire powers heat up his body and the bridge begins to crack. Jason manages to get Leo to the palace, but Thalia is left behind and says she will meet Jason at the wolf house.
After returning the venti and finding the location of Piper's father, Aeolus gives Leo a drawing he had made when he was only a small child and tells him that it is the key to his success. Soon after, he turns on the heroes after a voice tells him to, someone that is above the gods. Mellie, the wind nymph, helps them in their escape and when he wakes up, they are in a diner in San Francisco and Leo has a set of new clothes (thanks to Aphrodite, who had visited Piper in her dream). Piper tells them they are fighting Gaea and they should be careful from now on and avoid walking on land. They take a cab to Mount Diablo and begin to climb to the top, but Leo's feet begin to sink into the ground as Gaea is starting to wake up.
As they get closer, Leo makes a small wind up toy but isn't sure what it does, as he wasn't paying attention when he made it. When they reach the summit, Enceladus is waiting for them and summons a group of Earthborn to attack them. Leo tosses his toy into one of the construction vehicles and hops into another one, using the machine to destroy several of the monsters while Jason is fighting the giant. Soon, the vehicle is destroyed, but his wind up toy activates the other piece of equipment and it begins destroying more monsters until it too is deactivated. One Earthborn was left, but Leo had no more tricks or weapons. He lit himself on fire (he called this the blaze of glory) and charged, only for a dagger to chop the monster in half thanks to Piper.
Jason (with a lightning bolt from his father for help) defeated Enceladus and saved Piper's dad, flying back to the airport where Piper charmspeaks a pilot. Once they land and everyone is safe, they receive an Iris Message from Thalia that she found Hera at the Wolf House, so they borrow the chopper with Leo as the pilot. He is able to fly the chopper well enough thanks to his mechanical instincts, but sleet began to hammer the helicopter and they crash into the middle of a battlefield. They all retreat to the Wolf House, but Khione arrives and freezes all the Hunters, allowing the wolves and Earthborn to walk into the front door. She tells them that she was the one whispering into the ears of the gods and watching them for Enceladus. She was also the one that froze Festus' wiring, and plans on killing Jason and Piper so that the Roman campers will find their bodies and think that the Greeks have sided with the Giants. She offers Leo a place at her side because he is interesting, but he laughs her off and starts fighting her with his fire. The heat of his attacks begins to melt the ice and snow and many of the monsters run away in fear, including Khione herself as she turns to snow and disappears.
Leo then gets to work freeing Hera with an electric saw which he connected to a ventus named Tempest which was under Jason's command while Piper tries to charmspeak Gaea back to sleep to make the cage easier to break. While they do this, Jason is fighting off the newly awaken Porphyrion. Once the main support of the cage is broken, Hera broke free causing any monsters left in the house to run away or be dissolved by her true form. Porphyrion managed to get away, not wanting to fight when not at his full strength and Hera returns the demigods to camp. The trip causes Leo to throw up in one of the offering fires to the gods.
After telling everyone about their trip, Leo shows Piper, Jason, Chiron, and his cabin members the entrance to Bunker 9 and his fire powers. After searching the bunker, they find weapon ideas and designs, including a large war ship that matches the picture of the flying boat that Leo had drawn when he was a child. His cabin members elect him as Cabin Leader and make plans to make the Argo II and fly to Greece. He later attends the War Council as the leader of his cabin, and wonders why Jason picked Annabeth to sail with them. Jason then explains that if he is here at Camp Half-Blood, Percy must be at the Roman camp, called Camp Jupiter and that the Roman campers aren't as nice.
While Percy is dreaming, he sees Leo working on the Argo II when one of the engines explodes. He claims that it could take two or three days to fix and that the deadline to have the ship completed was today. When Percy, Frank, and Hazel are watching Polybotes from afar Ma Gasket, the Cyclops from The Lost Hero yells, "The camp, yes. Vengeance! The orange and purple ones destroy my home. Now Ma Gasket will destroy theirs! Do you hear me, Leo? Jason? Piper? I come to annihilate you!"
Later, when visiting Hazel Levesque's house in Alaska, Percy sees a picture of Sammy Valdez and thinks he had seen him somewhere before, but can't remember where. Hazel says he would be much older and Percy must just be imagining things. Percy then remembers his dream figuring out that Leo resembles Sammy almost identically.
Upon returning to Camp Jupiter and the defeat of Polybotes, Leo appears on a video scroll that was sent to Percy through Ella. He told them that he would appreciate it if the Roman demigods didn't shoot them out of the sky when they come to rescue Percy and start their quest. While watching the video, Hazel mistook him for Sammy Valdez and Percy remembers the picture of Sammy when looking at Leo.
Leo Valdez and the Quest for Buford
When Leo accidentally polishes Buford with Windex instead of Lemon Pledge with extra moisturizing formula, Buford runs off with two syncopators essential to building the engine for the Argo II. Leo, in a panic, asks for Jason and Piper's help to retrieve them. He explains the situation of how in about an hour, dangerous chemicals will mix in the engine blowing up the forest portion of Camp Half-Blood without the syncopators. With everyone caught up, the three friends journey into the forest in search of Buford. They then encounter Maenads on their journey and Leo feigns to be the Greek god, Dionysus, to please the Maenads. Suspicious, the Maenads figure out the truth and chase Leo and his friends until Leo comes up with an idea. Leo sends Jason to go find Buford, while he and Piper run towards Bunker 9. Once they reach Bunker 9, Leo distracts the Maenads with a party while he sets up a trap to ensnare them. Leo finally sets off the trap which drops a net (based on the original net which Hephaestus used to catch Ares and Aphrodite together) on the Maenads. Jason just in time arrives with Buford and Leo fixes the syncopator in the engine of the Argo II, thus narrowly preventing a massive explosion at Camp Half-Blood. Later Chiron and Argus arrive and decide to deport the Maenads away.
Leo is one of the five crew mates aboard the Argo II when it arrived at Camp Jupiter. He is possessed by an eidolon and attacks Camp Jupiter and New Rome. Percy is forced to knock him out while Annabeth piloted the ship away from the Romans. Following this incident, Leo wonders if his friends could ever trust him. Frank Zhang asks Leo if his name was Sammy, but he denies. Hazel Levesque soon reunites with the others as they land in Utah. Leo informs the others that he needs supplies to get the Argo II working again. Hazel volunteers to go and over the course of the journey, they share many awkward moments, much to Leo's dismay.
The two soon encounter Nemesis who Leo, at first, thinks is his Aunt Rosa. Nemesis tells him that he would always be the seventh wheel and offers her help in taking down the proud of mighty, which she claims Gaea and the Gigantes to be the proudest of all. She gives Leo a fortune cookie and tells him that he'll open it when he needs it most, but a painful sacrifice must be required. Leo tries to return it, but the fortune cookie seals itself away in his tool pocket. The goddess states that they had to save Nico by July 1st, the Kalends of July before Rome is destroyed. Nemesis then tells Leo to meet her cursed boy in the lake, before night where he gets agitated.
Leo and Hazel then meet Echo who Leo teases by having her repeat silly phrases. Echo leads them to Narcissus and his nymph fan club. Leo notes that Narcissus is looking at his reflection with a sheet of celestial bronze, one of the items needed to fix the ship. The demigods manage to figure out that Echo is trying to help Narcissus change his ways, but has proven unsuccessful. Leo tries to talk Narcissus into giving him the celestial bronze but fails. He then comes up with a plan and stations Hazel a few feet away and Echo in the nymph crowd.
Drawing tattoos on his arm and greasing his hair with motor oil, Leo struts out toward the love struck boy and claims he is better than Narcissus. Echo repeats everything Leo states and manages to trick the nymphs that Leo is better much to Narcissus' dismay. Distracted, Narcissus declares he is better as Leo continues to insult him. Hazel, using her powers, draws the celestial bronze towards her and runs toward the ship. Narcissus takes notice of the trick and orders the nymphs to catch the demigods. Leo helps Hazel with the sheet as Arion comes to their rescue. He tries to persuade Echo to come with them, but she decides to help Narcissus and gives him a kiss on the cheek. Leo states he'll never forget her, but his memory of her smile starts to fade as they reach the ship.
Leo grabs the supplies and manages to put the engine back together while Percy holds the nymphs back. The Argo II then heads back into the air, setting sail toward the Atlantic Ocean. He later calls a group meeting where they exchange notes on their enemies, and Hazel reveals that Rome would be destroyed in six days. Leo tells the group that he has to put down in order to finish repairs. Annabeth suggests someplace out of the way, but close to a city when Piper suggests Kansas. In the morning, Leo thanks Piper for not hating him after attacking New Rome the previous day. Piper then reassures she'll stick up for him and compares him to the annoying little brother she never had. On the deck, Piper explains her vision of Bacchus and Topeka 32. Leo states he and Festus calculated the mile marker as best as they could. He stays on board to fix the hull while Piper, Jason, and Percy head into Kansas. However, the trio soon realize that his calculations were wrong and are forced to summon transportation.
Leo helps Annabeth carry Jason and Piper toward the sickbay. He then heads the ship to Atlanta and retreats below deck for another meeting. He stops blaming himself for the attack on New Rome when Piper tells him that eidolons, possessing spirits, made him do it. The group discuss about Ephialtes and Otis, the twin giants, and how Romans would not follow them into the Mare Nostrum. Piper also informs that Gaea wants two of the seven demigod's to be killed. Leo remembers how Khinoe had stated Jason's blood would taint the Wolf House forever. He then proceeds to wonder if demigod blood has that power. Percy states that Polybotes had stated Percy's blood at Mount Olympus would wake Gaea.
Piper later states that the eidolons were still in the room and calls out to them with her Charmspeak. Leo tries to laugh her attempt off, but is taken over by the eidolon along with Jason and Percy. Piper tells the spirits to swear on the Styx that they would leave the ship and never possess anyone on the ship again. The eidolons leave which results in Leo falling on the floor because Frank didn't catch him. The next day, Leo grins when Percy and Annabeth are caught together in the stables, muttering classic over and over. At another meeting, Percy explains his dream about the twins and Nico. Leo makes a theory that Nico may be conspiring with the enemy while Jason backs him up. Hazel, outraged, storms out of the room, while Leo tries to apologize. Frank stops him angrily and Leo leaves to land the ship.
Percy, Frank, and Coach Hedge embark into Atlanta while Annabeth attempts to cheer up Hazel. Jason, Piper, and Leo are interrupted from their lunch to disembark, causing Leo to cry out if he can ever just eat a normal lunch. Percy tells him to head to Charleston where they can find a map to the Mark of Athena. Percy and Frank recount how they had met Phorcys, Keto, and the imprisonment of wild animals. They had also been imprisoned but escaped causing Leo to wonder if he's worth as much as two or three Franks. Frank, meanwhile gets himself trapped in Chinese Handcuffs, much to Leo's amusement. He changes into a lizard to escape which Leo jokes about. Percy then states that the map leads to the Mark of Athena causing them to wonder what it is.
Annabeth gears the conversation back to Charleston and wonders why Jason looked surprised to the name. He explains how he and Reyna had salvaged a ship, the C.S.S. Hunley for supplies, much to Leo's excitement claiming he wanted to see the Civil War artifact. Jason later explains how the Romans had fought for the Confederate side, much to Hazel's distaste. He then apologizes for it and his outburst in the meeting, forcing Leo to do the same. Jason then states he could lead a team to search for the map at the museum, which Leo volunteers for. Jason recruits Frank, who was playing with the Chinese handcuffs and couldn't get his fingers out. Leo laughs at Frank, stating there's a simple trick for escaping. He then mocks him in Chiron's voice when Frank turned into a lizard to escape. Jason then states that Reyna had a meeting with a ghost and she was never the same. Since the ghost only met with females, Annabeth, Piper, and Hazel agree to go.
Leo informs that Roman eagles were in their way and how he could send Buford as a distraction and go the long way to Charleston. Hazel then pleads that Nico would have less time, but Leo reassures her they'll have barely enough time to reach Rome and sends Buford, with a pair of Frank's pants, on his way. The next day, Leo docks the ship at Charleston Harbor and leaves with Jason and Frank to the museum. At the museum, they are attacked by Confederate ghosts and head back to the ship where Piper sends them an Iris-message that they're heading for Fort Sumter and Romans are attacking. Frank turns into a bald eagle while Leo grabs his talons and flies toward the Argo II with Jason behind them. Coach Hedge fires the ballista and knocks the three off course. Leo is dropped and the three disappear behind the fort. Annabeth tells them to draw back as she enters Fort Sumter, successfully obtaining the map and reunites with them back on the ship.
Leo desperately tries to man the ship as Percy and Jason create massive storms to keep the Roman demigods away. Leo punches in coordinates that Percy received from a nereid and they set sail into the Atlantic. After putting some distance, Coach Hedge takes the wheel and Leo asks where they are heading. Percy informs that the nereid had said Chiron's brothers would help them and that Keto is bound to send one of her sea monsters their way. Jason suggests they fly, but Leo says the air stabilizer is busted. Hazel worries and states Nico only has three days left, but Leo reassures her they'll make it if something unexpected happens. Frank wonders if there's any good news which Leo replies that Buford had successfully returned but without his pants. Annabeth and Piper tell Frank to help them take Jason and Percy, who were sapped out of strength, below deck. Leo wonders if he forgot something, but tries to dismiss it.
Hazel and Leo then stare at each other awkwardly and Leo tries to help her with her seasick. Hazel reassures Leo that Frank is a nice guy, but he is just nervous about his fire. Hazel asks Leo to remember about what had happened in the Great Salt Lake, and Leo states he'll be willing to use the fortune cookie to find Nico. Hazel rebuffs this and instead reminds him of how he handled Narcissus and the nymphs. She states that he reminds her too much of Sammy and she can show him who he was. Leo, determined to do what Frank did, grabs Hazel's hand and she shows him a flashback of her life.
Ghost Hazel and Leo watch as Hazel, bullied by Rufus, is saved by Sammy. Rufus had demanded Hazel for a diamond, but Sammy managed to take it instead, much to Hazel's horror. Leo is shocked that Sammy looks so much like him, but that he was smarter, cooler, and funnier. He figures out Sammy had stolen Hazel's heart, but he wasn't Sammy. The memory dissolves and the demigods arrive in Houston. Hazel states that this isn't from her memory, but Leo discovers that this is the spot where both of their timelines connect. An old man on the porch states Hazel's name and Hazel discovers Gaea had lied. Sammy was alive and well beyond the 1960's. Using Morse code, Sammy was tapping I love you over again to Hazel. Leo's mom, carries Leo to Sammy and tells him that he is Leo's bisabuelo, meaning great-grandfather in Spanish. Sammy takes Leo and tells him he'll be his stunt double, but Hera had stated he wouldn't be alive for Hazel's great danger and pleads to tell her he was sorry for selling the diamond. Sammy claims it was a good life, but it was cursed. He never saw Hazel again. Hazel starts crying as Sammy tells Leo he has his blessing and tell her hello to Hazel for him. He returns Leo to Esperanza and says he is ready to rest soon as the scene dissolves.
Back on the Argo II, the ship lurches to one side and Coach Hedge warns that one of Keto's monsters had found them. Leo curses himself for not changing the sonar as a skolopendra attacks. The rest of the crew head upstairs, but Percy and Jason are too tired to fight. Annabeth and Piper try to attack with their daggers as Frank shoots arrows and Coach Hedge attacks with his baseball bat. The satyr tells Leo that if he wasn't holding hands with Hazel for so long then the monster wouldn't have attacked. Frank, outraged and distracted, is knocked overboard. Leo and Hazel open a crate and take out jars of Greek fire. However, they are trapped by one of the monster's tentacles. Leo burns fire onto the tentacle and the monster drops them. Hazel and Leo throw the Greek fire into the monster's mouth as they sink underwater and slip into unconsciousness.
Leo wakes up in an underwater dungeon with Frank. He manages to convince him that he and Hazel are just friends, which Frank believes. The two then try to figure out a way to escape and Leo covers himself in fire, much to Frank´s horror as he backs away from him. Leo puts out the fire and Frank hesitates to tell him about his weakness. Just at that moment, the two are visited by a fish-horse otherwise known as ichthyocentaur. Frank is taken by Bythos, the combat teacher, while Leo is interrogated by Aphros, the home economics teacher. Leo tells Aphros his story which matches Hazel's much to Aphros' delight. Hazel reunites with Leo while Aprhos heads to find Frank. Leo manages to figure out that Frank's life is connected to a piece of firewood. Aphros, Bythos, and Frank meet up with Hazel and Leo where the ichthyocentaurs reassure that they will take action against Phorcys and Keto. Aphros tells Hazel to visit again with Arion and to save Nico the day after tomorrow as he will be vital to the quest. Aprhos informs Leo that he needs to stay close to Frank and Hazel, because they will face mechanical difficulties and sends them on their way with brownies.
The four demigods and Coach Hedge are relieved to see the three again as they make their way deeper into the Atlantic Ocean. They inform the crew that the ichthyocentaurs would protect the ship until they reach the Mare Nostrum. Percy, however, is disappointed that they didn't want to meet him. Leo informs they'll spend the next day flying to Rome and then the day after that, they'll arrive. Percy brings up the Mark of Athena, much to Annabeth's discomfort, calling it a problem. Annabeth tells them that the map she found would only show itself to her, but passes around a coin she received from her mother. Annabeth informs that the Mark of Athena would lead her to the Athena Parthenos, which vanished. Jason states that when he was praetor, an old legend was passed around that the Romans stole the statue, and that's why the two sides can never get along. Annabeth states she has to find the statue so she can mend the rift. After the meeting, Leo then assigns chores for everyone to do around the Argo II.
The next day, the group arrive at the Rock of Gibraltar, otherwise known as the Pillars of Hercules. An island appears in their way, blocking the path. Jason states that Hercules might be on the island and that he'll want to talk to them. Annabeth sends Jason and Piper on the island to converse with him while the others stay on board. Leo manages to fix the stabilizer in time for Piper's plan to unfold. The group manage to enter the Mare Nostrum as they fly away from Hercules. That night, after countless attacks, Leo stays manning the wheel while Percy and Annabeth discuss Percy's recent dream. However, they are attacked and kidnapped by a pirate, Chrysaor. The pirate kidnaps Piper, Hazel, Leo, Coach Hedge, and Annabeth while Percy and Frank manage to trick him away. Percy later plays tribute to his victory to Bacchus, and they sink the pirate's ship. The next morning, the group arrives in Rome.
Leo accompanies Hazel and Frank to the Pantheon where he discovers an underground tunnel behind the Tomb of Raphael. Hazel decides to head inside first, but Leo and Frank are forced to follow when they are attacked by eidolons. The trio head down the tunnel and enter a workshop, to Leo's delight. He exclaims that the inventions were the work of Archimedes and how he could upgrade the ship with his plans. However, Hazel and Frank are shocked by some of the incomplete inventions, controlled by eidolons, rendering them unconscious. Before they can get to Leo, he runs towards a room with folding metal gates and seals them together. The eidolons threaten to destroy Archimedes' Scrolls and kill Hazel and Frank unless Leo exits his prison. Leo tries to scan his surroundings and finds an Archimedes Sphere. He rapidly puts together the sphere, but doesn't have the access code as the ediolons prepare to attack. Leo breaks open the fortune cookie he received from Nemesis, and manages to complete the sphere. Leo manages to destroy the Taser Ball and possess one of the eidolons to battle the other one. Frank shields Hazel with his body and duck as Leo destroys the eidolons. Hazel wonders where Nico could be, and Leo points to Nico's Sword and states it was a trap. Gaea tells them that it was all a distraction as she traps them inside the workshop. She shows them visions of Annabeth facing her mother's mortal enemy and Percy leading Piper and Jason into a room.
Leo then rescues Percy, Jason, Piper, and Nico from Ephialtes and Otis as the twins are destroyed by Bacchus in the Colosseum. He states how he had Hazel create a tunnel, built and attached a distress signal to Frank the weasel, and led Coach Hedge to save them. Leo tells Percy that Gaea had shown them Annabeth in peril and they head to the Emmanuel Building. Along the way, Nico tells them that the mortal side of the Doors of Death are in Epirus, Greece in the House of Hades. He also informs that the Underworld side of the doors are in Tartarus. Leo blasts the ballistae into the parking lot, unknowingly smashing Arachne into a chasm that led to Tartarus. They disembark into the cave where Annabeth tells the group she defeated Arachne with Chinese Spidercuffs, a variation of Chinese Handcuffs. Leo thinks that they'll be able to fit the statue in the Argo II, but the lair started to collapse. Leo, Jason, Frank, Piper, and Coach Hedge try to secure Athena Parthenos from the Argo II. Hazel grabs the rope ladder, but tells them to cut Annabeth's ankle. Suddenly, Annabeth is dragged toward the chasm but Percy manages to catch her in time. Nico tries to save them, but Annabeth tells Percy to let her go. Percy denies and tells Nico to promise him that he'll lead the others to the Doors of Death in Greece. He and Annabeth then fall into Tartarus.
Leo says it is his fault for Percy and Annabeth falling into Tartarus, but Nico tells them they are not dead. He still blames himself though, and knows that the price for saving Hazel and Frank had been Percy and Annabeth. The six demigods decide to heed Percy's advice and Leo tells Festus to raise the sail so they can save Percy and Annabeth from the House of Hades.
Leo's ship, the Argo II, is attacked with giant boulders from earth spirits, known as ourae. He exclaims that he has fixed the mast on his ship three different times since they have tried to cross mountains to get to the House of Hades. Leo suggests that they wake up the others to help formulate a plan to getting over the mountains. He is shot down by Hazel twice. While they throw around ideas, Leo plays with his Archimedes sphere and ejects a 3D image of the mountain. Hazel spots something on the horizon and tells Leo to land on the ground. Leo reminds her that he can't land on the ground because of Gaea and states that he can float really close to the ground instead.
Later on in the book, Leo spends the night wrestling with the Athena Parthenos, because he's obsessed with figuring out how it works. After spending hours crawling over the stature, looking for some secret switch or pressure plate, he gives up his search and curls up in a blanket to sleep in the engine room.
As soon as he is asleep, he found himself in a dream. He was running for his life through his mother's old workshop, and although he couldn't see it, he was sure something was chasing him; something dark and full of hate. When he spotted the exit and sprinted towards it, he finds Gaea blocking his path. She tells him that she wants him to meet her favorite son. Although Leo darts left, away from the goddess, her laugh still echos behind him. She also says his death is near, before Leo's dream changes.
Now he finds himself at Camp Half-Blood, except now the camp is in ruins. Everything points to a big fire blazing through the camp. Leo keeps running, and feels the dark presence closing in on him. He weaves around bodies of fallen Greek and Roman demigods, and wants to check if they're alive, but he feels like he's running out of time. He jogged towards the only living people he could see, a group of Romans, and notices Octavian in the midst of the conversation. Octavian turns to face him, and startled Leo when he spoke in Gaea's voice, "This cannot be prevented. The Romans move east from New York. They advance on your camp, and nothing can slow them down".
Leo is tempted to punch Octavian in the face, but instead continues running, and climbs Half-Blood Hill. He falters to a stop as he notices that one side of the hill is shorn away. Beyond it, the entire world was gone, and all Leo could see were endless clouds. At a shattered pine tree, a woman kneels at a cave entrance that had cracked open between the tree's roots.
In the Blood of Olympus, Leo manage to see Annabeth's morse code message and came to where Jason, Piper and Annabeth were. When Leo, Percy, Frank and Hazel arrived at Olympia to help the victory goddess, Nike, to stop letting the gods suffer from their different aspects. They were force to fight each others, but they had another solution. They first killed all four of the Nikais or "Nikkettes" as Leo called those metal ladies.
In the final battle, Leo flies a restored Festus into battle against Gaea with Jason and Piper. After Jason gets Gaea high enough in the air and Piper puts Gaea to sleep with her charmspeak, Leo has Festus release his friends and then blasts Gaea with all of his firepower at the same time Octavian hits her with an onager. The combined attack destroys Gaea's physical form and scatters her essence, keeping her from forming a consciousness again or reforming like Ouranos and Kronos. The effort kills Leo and blasts Festus far away with his body, but Festus is able to resurrect him with the Physician's Cure.
At the end, he returns to Ogygia and takes Calypso back to the mortal world.
Leo is easygoing, upbeat, energetic, funny, flirty and loves to tell jokes, even if they aren't funny. Leo is genuinely very intelligent and honest, and cares about his friends and family. He sometimes doesn't think before reacting and he enjoys pulling pranks on people, especially those who he doesn't like. Despite his jokey attitude, Leo is emotionally scarred from the death of his mother and is crushed by guilt as he indirectly caused her death. He hides a hurt and angry demeanour with humour. Leo has been shown to have a serious side, which happens when he is angered by someone or when the situation calls for it. He is also seen building small bits of machinery and equipment and is very skilled and serious about his work.
He is also known to frequently fall in love with any beautiful girl as long as she is completely out of his league, such as in the case of Khione and Thalia. For example when Thalia, Jason and Leo were in the cave alone, Leo asked Thalia if her no-dating policy was seasonal, but she ignored him. Khione herself being a snow goddess, hates Leo as she can sense the fire within him and takes his compliments (Leo once called her hot) as insults. It is possible that this characteristic comes from his father, Hephaestus.
Near the end of The Lost Hero, he starts to let go of the pain of his mother's death and learns that his pyrokinesis is a gift and tool, not a curse. He also decides to stop running from his past and he starts opening up to his friends more. As of The House of Hades, After Leo visiting Calypso the first time, Leo became more steady and yet heartbroken, but he still made jokes frequently.
While Leo's fatal flaw has not been revealed, he shows feelings of inferiority - being unwanted or not trusted, the one no one wanted.
In The Lost Hero, Leo is described by Jason to look like a "a Latino Santa's elf," with curly black hair, dark brown eyes, pointy ears, a cheerful, elf-like face, normally with a mischievous smile on his face, and being of average height with a slim build. He is 5'6. His most notable trait is that he has a look in his eyes that makes him look like he has taken much more caffeine then the normal limit; this could be linked to his ADHD, although he is described as being even more ADHD than other demigods.
Abilities and Tools
- ADHD: Like most demigods, Leo possesses inborn supernatural battle reflexes and senses that he uses to analyze the fighting style of his opponent. According to Annabeth, however, Leo is seriously ADHD even for a demigod.
- Dyslexia: His brain is hard-wired for reading Ancient Greek instead of modern languages.
- Morse Code: Leo's mother taught him Morse code, a skill he has retained, and he was therefore able to understand Festus' last wish. As of The Blood of Olympus, Leo and Annabeth are the only known demigods to know Morse code.
- Trilingual: Leo can speak Spanish, Greek, and English fluently, having learned both English and Spanish from his mother as a child, and knowing Greek naturally because of being a demigod.
- Fighting skills: Despite receiving no known formal combat training, during the battle at the Wolf House in The Lost Hero, Leo displayed considerable combat skills by using two silver-tipped blacksmith's hammers to "smash any monsters that got in his way."
- Technokinesis: He has amazing mechanical abilities (even for a child of Hephaestus); he can manipulate a megaphone to say "The cow says moo" in a low voice like Darth Vader's and build a working helicopter out of pipe cleaners. He was able to fix the mechanical dragon Festus in one night, even though the rest of the Hephaestus cabin thought it was beyond repair and had to be destroyed. He even added wings to the dragon so it could fly.
- Machine Aptitude: Leo can understand and sense machinery and has the ability to expertly operate machines he has had no prior experience with. He can also communicate with machines such as Festus.
- Machine Expertise: Because Leo is a demigod child of Hephaestus, he can instinctively fly or drive any mechanical vehicle expertly, including cars, trains, or helicopters.
- Machine Sensitivity: He can sense faults in metal ore and identify machinery type and use by touch.
- Trap Detection: Leo can also sense traps, in particular mechanical traps, shown when he saw the hidden trap meant to catch Festus, and when he knew where all the defense mechanisms were in Midas's yard and disarmed them remotely.
- Pyrokinesis: He is the first demigod child of Hephaestus in hundreds of years to master the ability of pyrokinesis, the ability to generate and control fire. At low-level ability would probably be moving a candle back and forth; if better, maybe putting out the flame with his mind or making it relight. Pyrokinesis is one of the more practiced skills like telekinesis. It is too, for warming people up or setting objects aflame. His pyrokinesis is supposedly a curse, but he is determined to interpret it as a gift. His pyrokinetic abilities can go as far as to shoot white hot flames high in the air that could burn through a metal chain link. He was able to easily keep the upper hand against the snow goddess Khione for an extended period of time forcing her to go on the defensive, eventually forcing her to flee. An impressive feat given that fighting a god/goddess is "suicide," this is made even more impressive by the way Leo was going to completely overpower Khione and this could show Leo's power is comparable to that of a child of the Big Three. However, sometimes he has trouble controlling his pyrokinesis when he gets excited or scared, beginning to heat up and smoke. He can throw fireballs/fire bolts, fire blasts and (if he concentrates hard enough), columns of fire. However, this ability had no effect on the Gigantes Clytius.
- Superheated Fire: Leo can increase the heat of his fire (to the point that it becomes white-hot), and can also create walls of flame. This is the main defensive use of his powers.
- Supernova: Leo can increase the heat of his fire to such an extent that he basically becomes a supernova. He was able to use this ability to defeat Gaea, but the effects of using his power in such a way was fatal to him.
- Fire Immunity: He discovers he is fireproof (he can even survive a kerosene barrel explosion without feeling any pain, unlike Jason who feels the pain of heat but is unharmed by lightning). For example, when he was a small baby, Hera (in the form of Tia Callida, his "insane" babysitter) puts him in a blazing fireplace and he is completely comfortable. However, when he was attacked by Festus' firebreath, it did sting him slightly. Many other things like this follow.
- Heat Sensitivity: He can sense heat, flames, and metals, even allow him to walk through the forest at Camp half Blood at night, in the form of thermal vision.
- Magical Toolbelt: He has a magical tool belt that he uses constantly. He can pull simple tools from the belt, as well as food, medical supplies, and breath mints. The belt is seemingly endless and he doesn't know where it all comes from. However, larger items, especially things that don't have to do with mechanics, require the belt to recharge or "cool down." It is also known that big items, such as chain-saws, or magic items, like Jason's sword, Ivlivs, cannot be pulled out of the belt.
- His primary weapon is his 3-pound Club Hammer, which he summons from his tool belt from time to time.
- Festus the Bronze Dragon was repaired and managed by Leo after his discovery of Bunker 9, used in the American Civil war as the Hephaestus bunker. He supported Leo, Jason, and Piper, all the way to Midas's mansion, where he was destroyed by lasers to save Leo, Piper, and Jason. He was later used as the figurehead of the Argo II. By the end of the Blood of Olympus, Leo has secretly repaired Festus, building him a new body in the Argo II. After Leo sacrifices himself to stop Gaea, Festus brings him back using the Physician's Cure.
- Holographic Scroll- Leo's own invention, used in The Son of Neptune to alert Camp Jupiter, that the Argo II is coming.
- Buford- Leo's magical three legged table.
- Archimedes Sphere: Leo found it in Archimedes' workshop and repaired it. After that he was upgrading the sphere an made several copies. He can use it in different ways.
- The Physician's Cure - Ancient healing potion that can bring back the dead. The Seven put it together as part of their plan to defeat Gaea and Leo gave it to Festus who used it to resurrect him after Gaea's defeat.
|“||Nah, we were absolutely destined to meet your hot sister.||”|
–Leo talking to Jason about Thalia, in The Lost Hero
When Leo meets Thalia, Jason's sister, he falls in love with her. Leo hits on her, but she showed no signs of even acknowledging him. Leo took this as her not wanting to show how impressed with him she was, even though she was simply ignoring him. When him and Jason explained what had happened on their quest so far, he played up his own abilities. He also asked Thalia if the "Not Dating" rule all the Hunters of Artemis had to swear to was always or just a seasonal thing. Thalia just looked at him like he had evolved from pond scum, which only made Leo like her more.
|“||Lady, nobody messes with my dragon and gets away with it. I can’t believe I thought you were hot.||”|
–Leo to Khione, in The Lost Hero
When first meeting Khione, Leo states he acted like a total fool, but couldn't help it. While Jason and Piper where upstairs talking to Boreas, Leo had his clothes cleaned, his hair brushed, and took a pack of breath mints from his toolbelt in hopes of impressing her, but ultimately failed.
When meeting Khione again at the Wolf House, Khoine tried to use Leo's attraction to her against him. Saying that he could join her and become her champion, instead of following the path the Fates had given him. Leo on the other hand rejects her because of what she had done to Festus and comments that he can't believe he thought she was hot, something Khione, the snow goddess, takes great offense to.
|“||Leo was determined never to forget Echo’s face. She deserved at least one person who saw her and knew how good she was. Leo closed his eyes, but the memory of her smile was already fading.||”|
–Leo leaving Echo, in The Mark of Athena
Echo is a nymph that Leo met while on an island in the Great Salt Lake. While Leo originally teases her, as she is forced to repeat the last thing she hears, he stops after Hazel Levesque tells him to stop (as well as Echo turning his words against him). After meeting Narcissus and seeing how absorbed he is in himself, as well as all the nymphs loving him for his looks, he realizes that Echo is the only one that truly loves him for him and wants to save him. Echo helps Leo in his plan to steal a metal shield Narcissus is using as a mirror and aids in Leo's escape. While running away, she plans to fight off the nymphs that are after them. Leo sees her true face for only a minute and offers to bring her with them, but she refuses as she still loves Narcissus.
|“||"I'm coming back for you, Calypso," he said to the night wind. "I swear it on the River Styx."||”|
–Leo as he leaves Ogygia, in The House of Hades
In The House of Hades, Leo lands on Calypso's island, as the gods had not seen to Percy's wish of setting her free from Ogygia, her cursed home. Although Leo and Calypso do not get along very well when they first meet, when he works to escape, she turns out to be a great help and they become friends. They also share a kiss just before Leo leaves. Leaving Ogygia, Leo doubts that he really is "in love with an immortal girl" and that Calypso is in love with him. He then swears upon the River Styx that he will come back for Calypso.
Piper and Leo have been friends for a long time, meeting at the Wilderness School. Piper trusts him enough to tell him the truth about her father Tristan McLean, who is a famous movie star. Leo knows enough about her to know that she doesn't like when people fight her battles for her. When he was given fake memories by the Mist about Jason Grace, he had feelings of become a third wheel to Jason and Piper, something that begins to happen again when Jason and Piper start getting close all over again. Despite Piper being very beautiful, Leo never hits on her or asks her out, acting more like a brother who looks out for her. In The Mark of Athena, Piper gives him a sisterly kiss on the cheek after he returns safe and sound from Camp Fish-Blood, showing that she really does care for him, even if the two tease each other.
Despite their time at the Wilderness School being a trick from the mist, Leo still considers himself Jason's friend. He even volunteers to go on a quest with him and goes to repair the Bronze Dragon to give them a means of transportation. Despite Leo and Jason being good friends, Leo feels jealous of Jason. People look at Jason and respect him for being the son of Zeus (really Jupiter), while he only sees himself as the lowly mechanic. He also feels left out as Jason and Piper start to reform their relationship. The only time he doesn't feel jealous of Jason is when Thalia talks to Jason about his past and how Hera had taken him away from their mother. Leo remembers that while his own life wasn't that good, his own mother wasn't possessive of Hephaestus and only wanted Leo to know him.
Percy and Leo first meet in The Mark of Athena, but Percy saw images and visions of Leo during The Son of Neptune. They're not particularly close and haven't gotten to know each other well yet, as Percy was initially mad at him for shooting on Camp Jupiter. When Percy was mad at him, Leo was scared as he recognized the look as it reminded him of the times Jason summoned lightning. The two have also shown the same sense of sarcasm and at some times, stupidity. At the end of The Mark of Athena he is filled with guilt because he thinks opening Nemesis's fortune cookie was the reason Percy and Annabeth fell into Tartarus, in spite of Hazel and Nico's objections. Leo then vows to do whatever it takes to rescue Percy and Annabeth from Tartarus, despite thinking someone would have to stay in there to close the Doors of Death from both sides. In The Blood of Olympus Leo takes to jokingly call Percy Aquaman, much to the latter's annoyance.
Leo cares for Annabeth, but has been afraid of her ever since they first met at the Grand Canyon. The two have shown a bond through engineering and machinery. Aside from Leo, Annabeth is the only one who can operate the engine room. When he arrived at the Pantheon, Leo thought about how Annabeth would react to seeing it ("If Annabeth were here, she would've spent the whole day talking about it."). He is filled with guilt when she and Percy fall into Tartarus, feeling he is responsible.
Before meeting him in The Mark of Athena, Leo voices his doubts about Nico's loyalties, infuriating Hazel. Later on, after meeting him, Leo considers Nico creepy and intimidating, unlike Hazel. They have not gotten to know each other yet, but seem to be on good terms so far, as when Leo is overwhelmed with guilt about not saving Percy and Annabeth, Nico comforts him and assures him that they are alive.
In The House of Hades, Nico seems annoyed with Leo's frustration about constantly rebuilding the masts, saying that they don't grow on trees. Nico corrects him by calmly pointing out that they are made from trees. Leo is very much intimidated by the son of Hades, and never dares to tease him to his face. Nico, being far more serious, is frequently annoyed by Leo's sense of humor. However, after Leo returns from Calypso's island, Nico is glad to see him, and shakes his hand.
In The Blood of Olympus, when Hades reveals to Nico that one of the Seven is destined to die, the idea of any of them (including Leo) dying made him feel empty—like Nico was back in the dark Giants' Bronze Jar. Nico is quite saddened by Leo's death (having actually felt it happen), does his best to comfort Hazel about it, and prays to his father for guidance.
Interestingly, some things that Nico and Leo have in common, is that they both fluently speak a Romance language (Italian and Spanish respectively), they have both witnessed their mothers' deaths at the hand of a deity (Zeus and Gaea respectively), and they have both run away from places they used to call home (Camp Half-Blood and multiple foster homes respectively).
Hazel and Leo first meet in The Mark of Athena, but are very awkward around each other. Leo always feels like Hazel is watching him for some reason, but doesn't know why. He is also confused when she asks him if his name is Sammy, which it isn't. He also tries to avoid her to a small degree as he knows that Frank is dating her, but the two seem to end up together (sometimes with or without Frank). However, the two keep finding themselves in awkward situations that leads to a fight between Hazel and Frank.
While riding across the Great Salt Lake on Arion to get the Celestial Bronze needed to fix the Argo II, Leo holds Hazel's waist, noting that his heart is racing in doing this. He dismisses it, claiming it to be because of the speed they were going. Later, he calls her pretty.
Their connection to each other is slightly cleared up when Hazel uses her ability to show people the past to show Leo who Sammy was. During this flashback, it is shown that Sammy is Leo's great-grandfather and that he asked Leo to look after Hazel for him. Despite learning this information, the two are still somewhat skittish of each other. As of The House of Hades, the pair are now good friends as Leo is interested in Calypso.
Leo and Frank have a strained relationship. Frank is uneasy about Leo at first because of his similarity to Hazel's former love, Sammy. The two have contrasting personalities, Frank being far more serious and Leo's lack of control of what he says and his tendency to tease Frank. However, the two eventually become good friends when Frank reveals his weakness to Leo, and Leo later figures out how to help him. They have more of an understanding now, especially since Leo no longer has feelings for Hazel.
Leo is shown to love his mother very much. Esperanza is very protective and caring of him. The two had a very strong relationship and Leo was devastated when his mother died. He blames himself for her death, and for that reason, didn't use fire again until he needed to in order to help his cabin.
|“||She said Hazel’s great danger would not happen in my lifetime. But I promised I would be there for her. You will have to tell her I’m sorry, Leo. Help her if you can.||”|
–Sammy talking to a baby Leo, in The Mark of Athena
Leo has met his great-grandfather, but was not old enough to remember. The name 'Sammy' sounded familiar to him, but he couldn't place who it was. After looking at Hazel's past, the memories showed a moment where an old Sammy was talking to a baby Leo. Leo and Sammy have very similar personalities and appearances, which is shown when Hazel believes Leo to be Sammy. Leo however feels that he is only an imitation of Sammy after seeing Sammy's quick wit and how charming he was with the girls, unlike himself.
When Leo and Hephaestus first meet in The Lost Hero, it began with Leo telling him off for disappearing from his life. Hephaestus laughs at this, saying Leo reminds him of Esperanza, whom he misses quite a bit. Hephaestus later reveals that he has been watching Leo, and that he is very proud of him. He also admits that he is not very good with people, which is why he doesn't meet with his children often. When Festus is destroyed, Hephaestus takes his head to Bunker 9 upon Leo's request. In The Blood of Olympus, they meet again, and courageously fight the Giants side by side.
Leo hates his Aunt Rosa. After Leo's mom died, she blamed Leo for the death, calling him a devil. She turned the entire family against him, leaving him with no where to go. Because of her refusal to take him in, Leo was sent to a foster home, and his life of running away began. When Leo meets Nemesis he sees her in the form of Aunt Rosa, meaning she is the person he wants revenge from most.
Though not much is shown of Nyssa, Leo's first impression of her is that she is very serious. This is because of the Curse of Cabin 9. She is the one who explains the curse to him, and she congratulates him when he returns from his quest. She also helped him work on the Argo II, along with the rest of the Hephaestus cabin.
- He is currently the only known living son of Hephaestus who has been given the gift of Pyrokinesis. The previous one is Thomas Faynor known for having caused the Great Fire of London in 1666.
- This is also the year of the fire horse in eastern Zodiac.
- Because of his pointy ears and his friend Jason Grace calling his dad Vulcan instead of Hephaestus, Leo claims that he doesn't even like Star Trek, a reference to Spock, one of the main characters of Star Trek who is a Vulcan.
- He is the only one of the seven to not have lived in California at any point in life.
- The name Leo is a one of the twelve zodiac signs which has fire as it's element.
- In Latin, Leo means "Lion".
- In Teutonic, Leo means "Bold to his people".
- Leo, Nico di Angelo, Frank Zhang, Reyna Avila Ramírez-Arellano, Hylla Ramírez-Arellano, Annabeth Chase, and Hazel Levesque are the only known demigods that can speak two or more languages (that has nothing to do with them being a half-blood), as he, Reyna and Hylla can speak Spanish, he and Annabeth speak Morse Code, Nico can speak Italian, Hazel can speak Louisiana French, and Frank can speak Canadian French, along with "a little" Chinese.
- Leo looks almost exactly like Sammy Valdez, Hazel's old friend from the 1940's,
- This is because Sammy is his great-grandfather, as stated in The Mark of Athena. It could also be a possibility that Leo is Sammy's doppelganger.
- While Leo is a son of Hephaestus, he shares many traits with the children of Hermes, including elvish ears, a mischievous smile, and a love for practical jokes.
- It is said by Annabeth that even by demigod standards, Leo is seriously ADHD.
- Leo is the only known demigod who can go toe-to-toe with Khione and not freeze to death.
- Leo Valdez and the Quest for Buford is in his point of view.
- Leo's is the only known case of a demigod who met and befriended another demigod before either knew they were demigods.
- Leo once reprogrammed all the electronic billboards in Times Square to read "ALL DA LADIES LUV LEO!"
- It is stated in The Mark of Athena that Leo gets car sick.
- Leo has a cousin named Raphael and an aunt named Rosa, both of whom Leo doesn't like very much.
- In The Mark of Athena, Leo says "One basketball to rule them all". This is a pun on Lord Of The Rings, "One ring to rule them all".
- Leo's least favorite line in the prophecy is "To storm or fire the world must fall".
- He and Hazel Levesque are the only ones out of the Seven that have died and been resurrected. (Although Jason Grace might also qualify as resurrected, as Jason's soul was charmspeaked to return to his body by Piper McLean in The Lost Hero).
- His favorite color is red.
- Leo is the second known child of Hephaestus to die in an explosion. The first one was Charles Beckendorf.
- Leo is the only male demigod aboard the Argo II who wasn't praetor of the Twelfth Legion.
- Leo is the only demigod that had ran away seven times from foster homes.
- Leo is the only character who appears in the very first and the very last scenes of The Heroes of Olympus series.