All of Rick Riordan's book are set in the same universe, meaning that they all interact with each other and all interact with each other anyway from meeting in person to mentioning each other.

Camp Half-Blood Series and Kane Chronicles

The series makes occasional references to the Camp Half-Blood series, as it takes place in the same world.

The Red Pyramid

  • Amos Kane states that Manhattan has its own set of gods and that they must be kept separate from Egyptian gods. He says this while looking at the Empire State Building, the current home of Mount Olympus.
  • Thoth makes a vague reference to the Percy Jackson and the Olympians series when he mentions Hermes, who he states is nothing like him. This hints that he has seen Hermes and that the Greek and Egyptian gods might interact. This statement, however, might not be reasonable if he is inside a host, since the host isn't him. If this is the case, he might be comparing their true forms. He may not have a host, which would be more reasonable as he should he able to inhabit a place of learning in his true form like Anubis can in a place of death.
  • Anubis seems to have the same appearance as Nico di Angelo from the Camp Half-Blood Series. Also they have the same nickname, "Death Boy".
  • In the epilogue of the graphic novel, Sadie is seen wearing a Camp Half-Blood T-shirt and Carter is seen wearing an outfit nearly identical to what Percy Jackson wore on the cover of The Lightning Thief.

The Throne of Fire

  • Carter catches a glimpse of a winged horse flying around Manhattan, and recalls what Amos said about Manhattan and its gods. In The Son of Sobek, Carter believes that the winged horse is a Pegasi.
  • Carter makes another allusion to Percy Jackson, when he's drowning and wishing he had sea god powers.
  • The Roman ghosts that appeared later in the story mentioned the Roman gods Jupiter, Pluto, and Vulcan. Later, when they were destroyed by Ptah, he mentioned they went on to whatever afterlife awaits them, referring to the Underworld.
  • At the end of the graphic novel, Carter is seen wearing a Camp Jupiter T-shirt.

The Serpent's Shadow

  • Lacy and Drew from Camp Half-Blood make an appearance at a school dance that Sadie attends. In fact, Lacy even mentions that they go to a summer camp together and Drew is a tyrant there as well as at school.
  • Sadie's mom claims there will be other gods and rival magic that Sadie and Carter will encounter in the future, since the Egyptian gods have temporarily retreated from the mortal world.
  • Walt explains to Sadie that in the world of the gods (i.e., both the Camp Half-Blood series and The Kane Chronicles) that a person who dies and goes to the Underworld, they go to the one they believe in. I.e, if a believer is mummified, yet believes in the Greco-Roman Underworld, they will go to Hades'/Pluto's Underworld.
  • At the end of the book, Sadie says that they're picking up unidentified magical energy coming from Long Island. Camp Half-Blood is in Long Island.

The Son of Sobek

The Son of Sobek is a short story featuring both Percy Jackson and Carter Kane, with the audiobook narrated by Rick Riordan himself. In it, Percy Jackson and Carter Kane combine forces to defeat a common enemy. See The Son of Sobek for a full summary.

The Staff of Serapis

The Staff of Serapis is another short story featuring Sadie Kane and Annabeth Chase. Annabeth and Sadie combine forces to defeat Serapis, the Greco-Egyptian god. See The Staff of Serapis for a full summary.

The Crown of Ptolemy

Percy, Annabeth, Sadie, and Carter all meet up to defeat Setne, who wishes to become a god. See The Crown of Ptolemy for a full summary.

The Hidden Oracle

  • Apollo mentions Ra riding his sun boat across the sky.

Magnus Chase and the Gods of Asgard and Camp Half-Blood Series

The Blood of Olympus

The Sword of Summer

  • Magnus Chase is the cousin of Annabeth Chase.
  • Magnus wants his sword to turn into a pen (and jokes about how absurd it is), making reference to Riptide.
  • Annabeth appears in the beginning of the book, searching for Magnus, with her father, Frederick Chase.
  • Annabeth tries to convince Magnus to come to a place where he will be safe. She is talking about Camp Half-Blood or Camp Jupiter.
  • One of the chapter titles contain Jason Grace's name, though it says immediately after that Magnus has no idea who Jason is.
  • At the end of the book, Magnus and Annabeth meet up, and presumably tell each other about the different gods.

The Hammer of Thor

  • Magnus, since meeting up with his cousin, is now aware of the Greek Gods in New York City.
  • Annabeth tells Magnus about 'a fallen god', Apollo. As well as the trouble they are having with immortal Roman emperors. 

The Hidden Oracle

  • When Apollo goes to Percy's apartment, Percy mentions that Annabeth is in Boston for a family emergency.
  • Apollo mentions Sol, the Norse sun god, running from wolves across the sky.
  • Apollo mentions coming across a "hot God" in Stockholm and it references this god having a "Talking sword that won't shut up". This god is Frey.


Percy Jackson and the Olympians
Core Series: The Lightning Thief | The Sea of Monsters | The Titan's Curse | The Battle of the Labyrinth | The Last Olympian
Main Characters: Percy Jackson | Grover Underwood | Annabeth Chase | Tyson | Clarisse La Rue | Thalia Grace | Nico di Angelo | Chiron | Luke Castellan | Rachel Elizabeth Dare
Minor Characters: Travis Stoll | Connor Stoll | Mrs. O'Leary | Silena Beauregard | Charles Beckendorf | Sally Jackson | Paul Blofis | Blackjack | Zoë Nightshade | Bianca di Angelo | Juniper | Michael Yew | Ethan Nakamura
Olympian Gods: Zeus | Hera | Poseidon | Demeter | Ares | Athena | Apollo | Artemis | Hephaestus | Aphrodite | Hermes | Dionysus | Hades | Hestia
Minor Gods: Amphitrite | Ariadne | Hecate | Iris | Janus | Morpheus | Nemesis | Pan | Persephone | Triton
Titans: Kronos | Atlas | Calypso | Iapetus | Krios | Hyperion | Oceanus | Prometheus
Related Content: Rick Riordan | The Lightning Thief (film) | The Sea of Monster (film) | The Demigod Files | Demigods and Monsters | The Ultimate Guide | The Heroes of Olympus
The Heroes of Olympus
Core Series: The Lost Hero | The Son of Neptune | The Mark of Athena | The House of Hades | The Blood of Olympus
Main Characters: Jason Grace | Piper McLean | Leo Valdez | Percy Jackson | Frank Zhang | Hazel Levesque | Annabeth Chase | Reyna Avila Ramírez-Arellano | Nico di Angelo | Gleeson Hedge
Minor Characters: Rachel Elizabeth Dare | Thalia Grace | Octavian | Fleecy | Dakota | Ella | Tyson | Mrs. O'Leary | Arion | Hylla | Echo | Bob | Calypso
Olympian Gods: Zeus | Hera | Poseidon | Hades | Ares | Demeter | Athena | Apollo | Artemis | Hephaestus | Aphrodite | Hermes | Dionysus
Minor Gods: Achelous | Aeolus | Asclepius | Boreas | Keto | Khione | Thanatos | Iris | Hypnos | Hecate | Nemesis | Mithras | Notus | Triptolemus | Zephyros | Serapis | Kymopoleia | Nike | Phorcys
Roman Gods: Jupiter | Juno | Neptune | Pluto | Mars | Minerva | Ceres | Lupa | Bellona | Fortuna | Janus | Terminus | Vulcan | Mercury | Pomona | Aquilon | Hercules | Cupid | Auster | Favonius | Letus | Victoria | Orcus
Giants: Enceladus | Porphyrion | Polybotes | Alcyoneus | Ephialtes | Otis | Damasen | Clytius | Mimas | Orion | Hippolytus | Thoon | Periboia
Undead: Echo | Gray | Lityerses | Medea | Midas | Narcissus | Otrera | Phineas | Sciron
Primordial Gods: Gaea | Tartarus | Ourae | Nyx | Chaos | Ouranos | Akhlys | Erebos | Hemera | Elpis | Spes
Companion Books: Percy Jackson and the Olympians | Demigods and Monsters | The Ultimate Guide | The Demigod Files | The Demigod Diaries | The Son of Sobek | The Singer of Apollo | The Staff of Serapis | Percy Jackson's Greek Gods | Percy Jackson's Greek Heroes | The Crown of Ptolemy | Demigods & Magicians
The Trials of Apollo
Core Series: The Hidden Oracle | The Dark Prophecy | The Burning Maze
Main Characters: Apollo | Meg McCaffrey | Peaches
Minor Characters: Percy Jackson | Nico di Angelo | Will Solace | Rachel Elizabeth Dare | Kayla Knowles | Austin Lake | Chiron | Valentina Diaz | Damien White | Chiara Benvenuti | Laurel Victor | Holly Victor | Billie Ng | Leo Valdez
Olympian Gods: Zeus | Hera | Poseidon | Demeter | Ares | Athena | Apollo | Artemis | Hephaestus | Aphrodite | Hermes | Dionysus | Hades | Hestia
Minor Gods: Nero | Iris | Persephone | Britomartis | Commodus
Titans: Rhea | Calypso
Related Content: Rick Riordan | Percy Jackson and the Olympians | The Heroes of Olympus | Demigods & Magicians
The Kane Chronicles
Core Series: The Red Pyramid | The Throne of Fire | The Serpent's Shadow
Crossovers: The Son of Sobek | The Staff of Serapis | The Crown of Ptolemy | Demigods & Magicians
Main Characters: Carter Kane | Sadie Kane | Ra | Anubis | Apophis | Bast | Bes | Horus | Isis | Zia Rashid | Set | Walt Stone
Minor Characters: Michel Desjardins | Geb | Iskandar | Jasmine Anderson | Amos Kane | Julius Kane | Ruby Kane | Khufu | Nephthys | Nut | Osiris | Thoth | Leonid | Percy Jackson | Annabeth Chase | List of Characters
Other: House of Life | Magic | Magician | Kane Family
Related Content: Rick Riordan | List of Terms | The Kane Chronicles Survival Guide
Magnus Chase and the Gods of Asgard
Core Series: The Sword of Summer | The Hammer of Thor| The Ship of the Dead
Main Characters: Magnus Chase | Alex Fierro | Blitzen | Halfborn Gunderson | Hearthstone | Mallory Keen | Samirah al-Abbas | Sumarbrander | Thomas Jefferson Jr.
Minor Characters: Annabeth Chase | Frederick Chase | Gunilla | Randolph Chase | Percy Jackson | Amir Fadlan | Alderman | Inge | Helgi | Hunding | Lars Alhstrom
Norse Gods: Freya | Frey | Thor | Loki | Odin | Frigg | Ullr | Vidar | Heimdall | Sif
Minor Gods: Hel | Mimir | Ran | Aegir | Nine Billow Maidens | Sigyn | Norns | Njord | Skírnir
Jotnar: Surt | Utgard-Loki | Ymir | Thrym | Thrynga | Geirrod | Gjalp | Greip | Harald | Tiny | Hrungnir | Red | Tattoo (Giant) | Gunlod | Suttung | Baugi | Skakdi | Hyrm
Monsters: Ratatosk | Jormungand | Fenris | Wight | Brunnmigi | Lindworms | Nidhogg | Vedrfolnir
Magical Creatures: Sleipnir | Stanley | Marvin | Otis (Goat) | Elf | Dwarf | Jotunn | Hulder | Nøkks |

Vatnavaettir | Nisser