A Cyclops (plural: Cyclopes) is a one-eyed giant. They are very big, strong, and are considered to be ugly by most people.
A majority of the Cyclops are children of Poseidon, therefore making them Percy Jackson's half-brothers like Tyson, one of the supporting characters, who is now the general of the armies of Poseidon after defeating Typhon. They have superhuman hearing and can mimic any voice perfectly. This was done by Tyson to eavesdrop on various allies of the Titan Kronos, and by an unnamed Cyclops in Brooklyn to trick and trap a younger Luke Castellan, Annabeth Chase, and Thalia Grace. Ma Gasket, a Hyperborean Cyclops, also used this to try to eat Piper McLean, Leo Valdez, and Jason Grace. Most Cyclopes work in the forges of Hephaestus.
The first Cyclopes were raised by Ouranos and Gaea. Ouranos was not pleased with the monsters and imprisoned them until Kronos overthrew him. During Kronos' rule, he did not release the Cyclopes, so his mother Gaea, his son Zeus, and his wife Rhea plotted against him. In most cases, Cyclopes are abandoned by their parents when they are born in order to learn how to fight for themselves with the exception of Polyphemus. They mostly live in cities and are treated as outcasts or mistakes and they don't always come out right. No one wants them and they end up growing wild on the streets.
Cyclopes are also feared or avoided by most monsters, as even when they are young, they are still incredibly strong. Tyson, who is described as being a baby Cyclops, unknowingly frightened away other monsters, leading to Percy not being attacked all year. After the Laistrygonian Giant attacked Percy in the presence of Tyson, Annabeth commented that it was surprising they would even try to attack with Tyson around. Tyson was also able to beat most of the fully grown giants by himself without being injured.
It was revealed that when Percy was younger, he was stalked by a tall man in a trench coat and hat on the playground. The teachers finally threatened to call the police if the man didn't leave, and Percy always remembered how no one believed him when he told them the man had one eye under his hat. Thus, the man was actually a Cyclops who was for an unknown reason, good or bad, trying to keep an eye on Percy.
Percy while attending Meriwether College Prep, looked after Tyson; a child considered as the class project. It is later revealed by Annabeth that Tyson is a Cyclops, but Percy later learned he was also his brother. Tyson later helps on the Quest for the Golden Fleece by helping to defeat an evil and even larger Cyclops called Polyphemus, who had been using the fleece to lure satyrs to their deaths. In this novel, Percy discovers that the majority of Cyclopes are his half-brothers.
Tyson appears again on a break from his work in the underwater forges of Poseidon. He later goes on a quest with Percy, Grover and Annabeth. Along the way, they meet Briares, who was the only remaining one-hundred handed one.
During the final days of the Second Olympian War, Oceanus managed to invade the Underwater Forges Of The Cyclopes, forcing Tyson to lead the charge against the invaders. The Cyclopes later help Poseidon and the other Olympians drag Typhon to the deepest parts of Tartarus by wrapping him in chains. Tyson is later made the general of the Cyclops army.
Jason Grace, Leo Valdez, and Piper McLean met a family of Cyclops when they crashed in their factory in Detroit. Sump, Torque, and Ma Gasket then mimic voices to confuse Jason and Piper while Leo is outside trying to find Festus. By the time Leo comes back Torque tries to mimic Piper's voice, but later realizes that it was a trap and he is able to kill them with an engine block before the Cyclopes ate Piper and Jason. But instead of staying in Tartarus, they tried to reform, but by the time they do, Leo, Jason and Piper were already far away out of their reach and Ma Gasket swears to take revenge on them. She later says that she is proud of being a Northern Cyclops since they are much fiercer than the Southern ones.
It is revealed that the Northern Cyclopes had joined up with Polybotes in order to attack Camp Jupiter. Not only that, but they were being lead by Ma Gasket, who had reformed and still swears vengeance on Jason, Leo, and Piper. Before arriving at Camp Jupiter, the Cyclopes head to Napa for a winery tour, preventing Polybotes from attacking the camp as he needed their numbers. When the battle began, Tyson also appeared and fought against the evil Cyclopes, killing Ma Gasket himself.
Many Cyclopes were seen in Commodus's naming ceremony rehearsal.
There were different factions of Cyclopes:
Hyperborean (Northern) Cyclopes
A species of Cyclopes that often interact with Roman demigods. They fought for the Titans in the Second Titan War by building weapons and equipment. They often eat heroes and demigods. Typically smarter than Southern Cyclopes, The Northern Cyclopes use their building talents to make weapons like the squeaky war hammer and the exploding axe.
Weaponsmiths of the gods, the three eldest Cyclopes, and the sons of Gaea and Ouranos. They were the primeval gods of storms, like their brothers the Hekatonkheires, particularly of thunderstorms and lightning. They typically help Hephaestus in the forges. They are assisted by the children of Poseidon.
Many Cyclopes of Cyclops population are children of Poseidon, but some are children of other Cyclopes like Ma Gasket is the mother of Sump and Torque. Some help in the forges, some live in isolation, like Ma Gasket and Polyphemus. The Southern Cyclopes are mostly children of Poseidon and the northern ones bred by Cyclopes.
Southern Cyclopes are sheep Herders in the Sea of Monsters. However much like the Northern Cyclopes, they also often eat heroes and demigods. The Southern Cyclopes often interact with Greek demigods and are typically malevolent. They seem to be not as smart as Northern Cyclopes since they don't use their building talents and instead herd sheep. It is also noted that in The Sea of Monsters, Polyphemus is not as smart as Ma Gasket in The Lost Hero, as Polyphemus doesn't know what a mango is and is repeatedly tricked by Grover. He is also shown he is bad at math.
- Immunity to fire/extreme heat. - exception of the Flames of the River Phlegethon
- Extraordinary aptitude/ability with inventing, mechanics, etc.
- Extremely long living.
- Superhuman hearing.
- Ability to mimic a person's voice almost perfectly.
- Able to withstand many physical blows/attacks.
- Superhuman strength.