The Heroes of Olympus
||This article describes a work or element of fiction in a primarily in-universe style. (September 2011)|
The logo for the The Heroes of Olympus series
|Genre||Fantasy, Young-adult fiction, Mystery, Greek and Roman mythology|
|Media type||Print (hardback and paperback)
|Preceded by||Percy Jackson & the Olympians|
The Heroes of Olympus is a collection of five fantasy novels by American author Rick Riordan, scheduled to be completed in October 2014. This series chronicles the adventures of seven demigods in their race against time to prevent the awakening of the earth goddess, Gaia. The first novel, The Lost Hero, continues the story from where it left off in The Last Olympian, the last novel in the preceding series Percy Jackson & the Olympians. The Heroes Of Olympus series recounts the succeeding Gigantomachy of Greek and Roman myth in The Last Olympian outlines the events of The Heroes of Olympus. Demigods, living secretly in the modern era, are featured in both series as they fight against gods and Titans as they did in the past. The Heroes of Olympus introduces Roman demigods: children produced by the Roman gods, who are separated from their Greek counterparts. These two groups of demigods are enemies due to a stolen statue of Athena, and have been forced apart for centuries, but must unite to stop the chief antagonist in the series, Gaia, from gaining control of the earth. Percy Jackson, the protagonist of the previous series, is one of the seven main characters.
- 1 Background
- 2 The books
- 3 Supplementary works
- 4 Main characters
- 5 References
- 6 External links
Prophecy of Seven / New Great Prophecy
Known as the "New Great Prophecy" to the Greeks and the "Prophecy of Seven" to the Romans, this prophecy, introduced in The Last Olympian, guides the characters through the series. The prophecy reads:
"Seven half-bloods shall answer the call,
To storm or fire, the world must fall,
An oath to keep with a final breath,
And foes bear arms to the Doors of Death."
The seven demigods to which the prophecy refers are: Percy Jackson, son of Poseidon; Annabeth Chase, daughter of Athena; Jason Grace, son of Jupiter; Piper McLean, daughter of Aphrodite; Leo Valdez, son of Hephaestus; Hazel Levesque, daughter of Pluto and Frank Zhang, son of Mars. Percy Jackson and Annabeth Chase were introduced in the first series, Percy Jackson & the Olympians.
The Lost Hero
The Lost Hero, the first book in the Heroes of Olympus series, was released on October 12, 2010.
The giant's revenge, the seven shall birth
And death unleashed through Hera's rage."
Jason has no memory of his identity or how he came to be on the bus with a group taking a field trip to the Grand Canyon. Leo claims to be his best friend and Piper claims to be his girlfriend. At the Grand Canyon, a horde of Venti attacks the three and their supervising teacher, Coach Gleeson Hedge, who reveals himself to be a Satyr and confronts the Venti. Jason is able to defeat the Venti's helpers, but the Venti capture Coach Hedge and flee. Two strangers arrive in a flying chariot: Annabeth (daughter of Athena) and Butch (son of Iris). Annabeth is hostile towards Jason when they meet, because she had a vision in which Hera gave her a clue concerning the whereabouts of her missing boyfriend, Percy Jackson, saying that, to find Percy, she had to find the guy with one shoe (Jason lost a shoe in the fight), but Percy was not there when she arrived.
Jason, Piper, and Leo are taken to Camp Half Blood and are informed that they are demigods, children of the ancient Greek gods. Leo and Piper are claimed by their godly parents, Hephaestus and Aphrodite respectively. Piper also forms a rivalry with Drew, the bossy senior counselor of her cabin. Jason is revealed to be a son of Zeus after he summons his power to call lightning. He is also revealed to be the brother of Thalia, a main character from the Percy Jackson series. Jason remembers Thalia when he sees a picture of her in Zeus's cabin and learns that Hera/Juno has stolen his memories. Piper is jealous of Thalia at first, until she realizes that Thalia is Jason's biological sister. Annabeth takes Jason to see a son of Hypnos (god of sleep) to try to find some of his memories through sleep. The son of Hypnos explains to him the difference between the gods' Greek and Roman forms. Less than a day later, the three new demigods are sent on an urgent quest to rescue Hera, who has been kidnapped by a giant. The three set off on the back of a giant robotic dragon, Festus (in Latin, Festus means "happy") that Leo finds and repairs. Along the way, Jason, Piper and Leo meet and confront Boreas, three Cyclops, Medea, King Midas, King Lycaon and his pack of Werewolves, and Aeolus. They discover that Hera's kidnappers are Gaia's underlings and that she seeks to overthrow the Olympians.
They save Piper's father (Tristan McLean, a movie star), whom Enceladus has held ransom, and release Hera from her prison. They temporarily stall Gaia's plans, but the newly risen Porphyrion is able to escape. After the battle, they return to camp, where Leo starts building the Argo 2,the flying ship for their next mission. Piper also overthrows Drew as senior counselor and gains new-found self-confidence. After part of his memory returns, Jason realizes that he is from the Roman counterpart to Camp Half-Blood called Camp Jupiter. He remembers a girl named Reyna and that Hera switched his place with Percy Jackson, who is now at Camp Jupiter with no memory of his life at Camp Half-Blood.
The Son of Neptune
The Son of Neptune, the second book in the Heroes of Olympus series, was released on October 4, 2011.
"Go to Alaska.
Find Thanatos and free him.
Come back by sundown on June twenty-fourth or die."
The Son of Neptune opens with Percy Jackson being chased by two gorgons, Stheno and Euryale, who hate him for killing their sister Medusa. They reveal that they're working for Gaia. While making his escape, Percy runs into an old woman named June, who reveals herself to be Juno (Hera) and gives him a choice: do her a favor or live safely under the sea while everybody and everything is destroyed. As the favor, Percy carries her across the Little Tiber, which is a powerful river. In the process, he loses his invincibility from the River Styx. When he reaches his destination, he meets Hazel Levesque, a daughter of Pluto, and Frank Zhang, a son of Mars. Percy saves Frank from the Gorgons by drowning them.
Percy is taken into the camp after Juno introduces him to Camp Jupiter. Reyna seems to recognize him, but refuses to acknowledge him. She and her sister lost their home during Percy's attack (in Percy Jackson and the Sea of Monsters). She sends Percy and Hazel to Octavian, the camp augur, to determine whether or not he's fit to join the legion. Along the way, Lares, the camp's ancestral spirits, call him Graceus, or "Greek," worries Hazel. When they reach Jupiter's temple, Octavian is cutting teddy bears open and reading the stuffing. Octavian threatens Hazel by telling her that if she doesn't vote for him, he'll reveal her secret. He declares good omens, and Hazel and Percy go to the temples, where they meet Nico di Angelo, a main character from the Percy Jackson series. He knows Percy, but claims he does not recognize him. Meanwhile, Frank is organizing weaponry when a Lare appears and tells him he knows about his stick and his birth. Frank runs off to find Hazel and Percy. He takes Percy to the baths while Hazel and Nico talk. Hazel reveals that she's from the 1940s and has a blackout. She realizes that she's late for the role call, so she and Nico rush to line up.
During war games, a Camp Jupiter activity, Percy impresses everyone with his battle skills and instincts, even though they are not Roman tactics and are more Greek-style. After the games, Octavian deliberately hurts a girl (Gwen). She is severely injured and dies, only to come back to life a few moments later. Mars, the god of war, appears and informs the campers that "death has been chained" and claims Frank Zhang as his son. Mars insists that Percy and Frank must go on a quest to free Thanatos, the god of death. He has been captured in Alaska and is no longer able to keep mortals dead. Frank requests that Hazel accompany him on the quest, and they set off towards Alaska.
While travelling on their quest, Percy struggles to regain his memory. Time and time again, he recalls things but is never able to determine from where. His only clear memory is of a girl named Annabeth. Hazel reveals that she died long ago, but her half-brother Nico Di Angelo, son of Hades, saved her from the Underworld. Frank tells the other two that he was given a piece of wood that is tied to his life. If the wood burns completely, he will die. After they experience many events and monsters (including basilisks, giants, and an unexpected meeting with the Amazons), they meet Reyna's sister, who helps them and gives Hazel a powerful horse named Arion, who only eats gold and is a son of Neptune. They finally arrive in Alaska, where they find Thanatos in chains, which can only be broken by the fire of life (referring to the piece of wood tied to Frank's life). Percy defends Frank while he melts Thanatos' chains with his burning stick, losing more and more of his life. Hazel attacks Alcyoneus, the giant born to oppose Pluto. Thanatos is eventually freed and with the help of Hazel's horse, Arion, and they drag the giant out of its land of Alaska to Canada where it is able to be killed.
Percy regains his memory as they race back to Camp Jupiter. Knowing that the camp is under attack, Percy takes charge and leads the Romans into battle with the help of some of his old friends from Camp Half-Blood and the Amazons. The morale of the Romans is recharged after they discover that Percy recovered the camp's lost standard, which had been missing for years. Percy challenges the giant, Polybotes (the giant born to oppose Neptune), to a duel and calls to Terminus, the Roman border god, to help him defeat the giant. Percy has been told that only when gods and demigods work together can the giants be defeated. He defeats Polybotes by using the head of Terminus' statue as a weapon. The camp names him a praetor, a leader of the Roman camp. The Greek demigods from Camp Half-Blood appear in the flying ship Argo II sailing towards the camp. The Romans argue over attacking the ship. As praetor, Percy orders them to hold their fire. If the Greeks attack, he would be to blame, but he is not worried. With his arms around Frank and Hazel, he approaches his "other family".
The Mark of Athena
The Mark of Athena, the third book in the Heroes of Olympus series, was released on October 2, 2012.
"Wisdom's daughter walks alone
The Mark of Athena burns through Rome,
Who holds the key to endless death,
Giants' bane stands gold and pale
Won through pain from a woven jail."
After sending Leo's video to Camp Jupiter, Argo II prepares to land on the Roman camp's border, but Terminus, the god of borders, stops them, for no weapons are allowed inside. It is then decided to let the ship stay in the air while Annabeth, Leo, Piper, and Jason meet the Roman campers. Percy Jackson, together with Hazel and Frank, welcomes the Greek demigods and Coach Hedge. They hold a reunion and, during the conversations, Ella, the harpy, speaks about a prophecy that refers to Annabeth's quest for the Mark of Athena. Piper uses her charmspeak in order to divert the topic. While Jason gives Piper a tour of the camp, Reyna talks to Annabeth alone.
During their conversation, the Argo II, which is controlled by Leo Valdez (who was possessed by Eidolons), fires at Camp Jupiter. The Romans defend their bases, and Annabeth, Piper, Jason, and Percy rush inside the Argo II to stop Leo from firing on the campaign. They start to leave the camp, while Hazel and Frank delay the Roman campers. The Argo II becomes damaged and, when Leo lands for repairs, they encounter Echo and Narcissus. They are told that they have to search for the Mark of Athena to bring the Romans and the Greeks together.
During their journey, they meet Phorcys and Keto. The seven quickly leave for Charleston. Annabeth, Piper, and Hazel go to Battery Park to find a mysterious ghost, which happens to be Aphrodite. Jason, Leo, and Frank go to a museum in Fort Sumter. Only the girls' story is told. Aphrodite tells them about their love lives and the other Olympians that are suffering from confusion about their Roman or Greek identities. After their talk, the angry Romans arrive, and war breaks out. Annabeth meets Reyna, who is in Fort Sumter to retrieve a map which will save her friends. Reyna begs Annabeth to come with her and die a painful death to save her camp, but Annabeth tells Reyna that she will only follow the mark.
The seven reach the ship and leave safely to go to Chiron's brothers, who live in the sea. During the ride, they are attacked by a shrimp monster. Leo, Frank, and Hazel go underwater and find icthyocentaurs, Chiron's brothers, who find the three's story interesting and speed their way to Rome. They meet Hercules near the pillars, at the entrance to Rome, and Piper and Jason get the second horn of Achelous, the bull-headed river god. Even though it was Hercules who ordered them to cut it off, Piper decides that Hercules does not deserve the horn and keeps it for herself. She brings forth a pile of food, and Hercules falls.
The seven cross the pillars and sail into Rome. Annabeth has to find the Athena Parthenos by following the Mark of Athena and battle its guardian Arachne. Percy, Jason, and Piper travel into an underground area and battle the twin giants, Otis and Ephialtes, the anti-Dionysus. Frank, Hazel, and Leo travel in search of Nico, and find Archimedes' scrolls on spheres. In the end, Annabeth outwits Arachne by tricking her into weaving her own trap. Percy and Jason battle the giants and, with very little (emphasis on "very little") help from Dionysus's Roman counterpart, Bacchus, they rescue Nico, and Bacchus defeats Otis and Ephialtes by throwing a pinecone into their eye.
Frank, Hazel, and Leo battle the Eidolons and rescue Archimedes' scrolls and one of his spheres. They meet, and Annabeth secures the Athena Parthenos. However, Arachne pulls Annabeth into Tartarus by some spider silk as the statue is lifted onto their ship. Percy follows Annabeth by not releasing the line with which he was trying to pull her up. After Percy and Annabeth fall into Tartarus, the remaining five prophecy demigods, Coach Hedge, and Nico conduct a meeting. Nico says Percy told him to lead the demigods to the Doors of Death, and he and Annabeth would meet them at the end of Tartarus on the Doors' other side. Nico and Hazel both say they are fairly sure Percy and Annabeth are not dead yet. The book closes with Leo telling Festus the Dragon figurehead to set sail: they have friends to save.
The House of Hades
The House of Hades, the fourth book in the Heroes of Olympus series, was released on October 8, 2013.
Approximately nine days after the events in The Mark of Athena, Hazel and the others are struggling to get past the Apennine Mountains because they are being stopped by numinas, rock gods. She prays to her father Pluto for help, and he sends Arion, who takes her into a storm, where she meets Hecate, the goddess of magic and crossroads. Hazel is given four choices from which to choose, to continue on her journey. Hazel chooses to take Hecate's secret path to get across the Apennines. She informs Hazel of her special gift, and tells her what to do when she crosses the Apennines.
Meanwhile, Percy and Annabeth are falling towards Tartarus. Shortly after arriving in Tartarus, Annabeth and Percy find the River of Fire and drink from it, which makes them immune to the harsh Tartarus environment, albeit temporarily. Annabeth and Percy follow some Empousa, including Kelli (originally seen in Battle of the Labyrinth), to try and find the Doors of Death. Percy and Annabeth eventually are spotted and almost killed, until Bob (the name to which Percy changed Iapetus's name in The Demigod Files: The Sword of Hades when he dragged Iapetus—a Titan—through the River Lethe) comes and helps vanquish them. Bob leads them to The Shrine of Hermes, where Annabeth successfully sends a message back to Camp Half-Blood. Bob joins them on their journey to the heart of Tartarus.
Leo dreams of being chased by someone in the shadows. Two dwarfs attack and steal from the ship. Leo and Jason recover their items, along with Odysseus's astrolabe and an ancient book, which they return to Triptolemus, an agricultural god, in Venice. Hecate teaches Hazel how to use the Mist. In Venice, they encounter many katoblepones, creatures that exhale poison. Hazel is struck by poison and loses consciousness. Triptolemus refuses to heal Hazel unless he gets another python for his chariot. Frank sets out to successfully destroy all the katoblepones in Venice. Ares and Mars, who have been fighting inside Frank's head since the Greek and Roman demigod armies met, temporarily call a truce and reward Frank. On their way to Greece, the Argo II is attacked by a giant turtle and the bandit Sciron. Using her gift, Hazel manipulates the Mist and kills Sciron. Her father, Pluto, appears and gives her more information about the House of Hades. Jason dreams of Rachel and Grover passing on the message from Annabeth to Reyna. Reyna decides to venture to the Ancient Lands, and get the Athena Parthenos to prevent war between the Greeks and Romans.
Jason tells Leo that they need to make a stop in Croatia. There, Jason and Nico meet up with Cupid. After Nico admits to having been in love with Percy, Cupid gives them Diocletian's Scepter. Back on the ship, Leo is blown into the sky and Piper is left alone to fight Khione, the goddess of snow, who has frozen the others. Piper kills Khione by using charmspeak to bring Festus to life. Leo lands on Ogygia, where he meets Calypso, despite Percy having made the gods swear to release her at the end of The Last Olympian. At first, they hate each other, but they begin to develop feelings for each other as they spend time together. Leo wants to take Calypso with him, but she's cursed to fall in love with heroes and then lose them. As Leo heads back to the real world, he swears on the River Styx to come back for her, knowing that the prophecy contains the line: "an oath to keep with final breath". Meanwhile, Jason has to meet with Auster, the Roman god of the south wind, whom he convinces to allow them to pass his realm, providing Venti (storm spirits) to help them until they find Leo, who can fix the ship. Jason harnesses the storm spirits and takes the Argo II back north to Greece where they meet up with Leo.
Meanwhile, Annabeth and Percy meet Nyx (Night) in Tartarus. Annabeth devises a plan to trick Nyx and her children into blinding each other with darkness, giving Annabeth and Percy time to flee into the Mansion of Night, where they meet up with Bob. Annabeth, Percy, Bob and Small Bob (Bob's new-found pet cat, first seen in The Titan's Curse at the Museum of Natural History) then head directly towards the Doors of Death. As the group trudges amidst the colossal number of monsters, they encounter Hyperion and Krios, who are guarding the Doors of Death. Just as they are about to cut the chains securing the Doors, Tartarus appears in person, destroys the Titans, and removes the Death Mist from Percy and Annabeth. Percy is traumatised and loses all will to fight, while Annabeth is void of ideas. Bob challenges Tartarus and, just when he begins to lose the battle, Damasen charges into the battle with his drakon, declaring that he has decided to choose his own fate. With Damasen holding off Tartarus and Bob securing the Doors of Death, Percy and Annabeth finally escape Tartarus, but not before Bob says, "Tell the stars hello."
In the mortal word, the crew soon notices that Leo has changed. Although he still retains much of his liveliness, the encounter with Calypso has changed him. With an ominous storm brewing ahead, the crew heads towards their final destination—Epirus. Nico and Hazel lead the way into the Necromanteion. After descending two levels, the crew are ambushed by a swarm of monsters. Leo and Hazel are separated from the others. Nico, Piper, Jason and Frank begin to mount an attack on the monsters, but are soon overwhelmed, as Nico's army of dead Roman warriors are left wandering aimlessly without proper commands. The turning point of the battle comes in the form of Frank, whom Jason promoted to praetor, commanding the warriors and leading the army.
On the other side of the cave, Leo and Hazel encounter Pasiphae and Clytius who are guarding the Doors of Death. Hecate has predicted that Hazel and Leo would meet these enemies. Pasiphae warns that someone is required to push the "Up" button on the Doors of Death and, if Hazel and Leo fail to win this battle, Percy and Annabeth will be trapped for eternity. The battle begins with Hazel and Leo being trapped in Pasiphae's Labyrinth. Hazel soon figures out that she could use her Mist powers to trick Pasiphae into believing what she wants to see most—that the heroes are trapped in her Labyrinth. Hazel soon overcomes the Labyrinth and defeats Pasiphae by launching her into a trapdoor made by her Mist. Hecate appears and aids Hazel in battling Clytius. He is soon defeated, but Leo manages to open the doors for Percy and Annabeth with a well-aimed screwdriver. Hazel manages to cut the chains that bind the doors to the Necromanteion. Just when the allies are defeated, Frank, Piper, Jason and Nico appear and collectively defeat Clytius with the help of Hecate. Finally, just as the cave collapses, Nico, with the help of Hazel, shadow-travels the crew out of the cave.
In the mortal world, the crew is joined by Reyna, who has made it to the ship, losing her pegasus Scipio in the process. While discussing their next course of action, the crew decides that the Athena Parthenos must be transported to Camp Half-Blood, and they must head towards Athens to face the giants. With only two weeks left before the revival of Gaea at the Feast of Spes, the crew is unable to decide where to go. After much debate, Nico volunteers to shadow-travel with Reyna and Coach Hedge back to Camp Half-Blood, while the crew can head towards Greece. The book concludes with Percy saying to the stars, "Bob says hello."
The Blood of Olympus
The Blood of Olympus, the fifth and final book in the Heroes of Olympus series, is set for release on October 7, 2014.
The seven united Greek and Roman demigods of the Argo II crew journey to Athens in a final attempt to prevent Gaea from awakening and destroying the earth, while Reyna, Nico, and Coach Hedge travel with the Athena Parthenos in tow to Camp Half-Blood, hoping to prevent war between the massed groups of Greek and Roman demigods, and to unite the two groups. Gaea will rise if two of the seven on the quest are sacrificed to her during the Feast of Spes, and her children, the powerful, already risen giants, can only be defeated by demigods and gods working together. With the Greek and Roman aspects of the gods warring within each deity, the gods are incapacitated, yet the questing demigods must somehow save the planet and all who live on it from the earth mother herself.
The Demigod Diaries
Released August 14, 2012, The Demigod Diaries is a collection of short stories. Similar to The Demigod Files, it contains some new stories with character interviews, illustrations, puzzles, and a quiz. The four stories include:
- "The Diary of Luke Castellan": Thalia and Luke meet Annabeth in Richmond, Virginia, after a disturbing encounter with a cursed, reclusive son of Apollo, before the Percy Jackson & the Olympians series.
- "Percy Jackson and the Staff of Hermes": Percy and Annabeth are sent by Hermes to retrieve his caduceus from the fire-breathing giant Cacus.
- "Leo Valdez and the Quest for Buford": Jason, Leo, and Piper confront crazed Maenads while searching for Buford the table, which has absconded in a fit of pique, at Camp Half-Blood between The Lost Hero and The Son of Neptune.
- "Son of Magic": Alabaster Torrington, a demigod son of Hecate who fought on Kronos' side, finds himself in a fight to the death with Lamia after being banished from Camp Half-Blood following Kronos' defeat in the Second Titan War in The Last Olympian, and seeks the help of a well-known expert on death. This story was written by Rick Riordan's son Haley Riordan.
- Perseus "Percy" Jackson: The powerful 17-year-old son of Poseidon (Roman form: Neptune), he is one of the Roman praetors. He is one of the most powerful living demigods, being the son of a "Big Three" god, along with Hazel, Nico, Thalia, and Jason. He is described as very handsome, with sea green eyes and black, messy hair. Percy was born on August 18. He has the power to control water and has perfect bearings at sea. He can breathe underwater and communicate with sea creatures and horses, including pegasi. He carries a sword called "Riptide" (Ancient Greek:[Anakulusmos] Ανακλυσμός). He fought the Titan Hyperion with the help of Grover and the Titan Kronos. He is the star of Camp Half Blood and was swapped with Jason Grace of Camp Jupiter by Hera (Roman form: Juno). He was the star of Camp Half Blood, and when he was swapped to Camp Jupiter, he was made the Praetor after his adventure of destroying the immortal giant Alcyoneus and bringing back Thanatos. He is a major part of the Second Great Prophecy. He is dating Annabeth Chase, daughter of Athena.(Even though Athena doesn't really approve)
- Annabeth Chase: A 17-year-old daughter of Athena (Roman form: Minerva), she is highly intelligent, wise, and always ready with a plan, a back-up plan and the back-up of the back-up plan. She was born on July 12. After the war against Kronos, the Olympians crowned her "Head Architect of Olympus," as Percy destroyed Olympus in the process of saving it. Annabeth is known to be part of the Second Great Prophecy and, to this effect, leads the Argo II to Camp Jupiter. She is the girlfriend of Percy Jackson, son of Poseidon. Annabeth wants to bring peace by following the Mark of Athena and finding the stolen statue (Athena Parthenos), dedicated to her mother. She doesn't completely trust Jason Grace at first, but eventually comes to common terms with him, as she is best friends with his sister Thalia. She is one of the smartest demigods, and is able to outwit Arachne in order to save the Athena Parthenos. When Annabeth was seven years old, she ran away from her home, only to face monsters and eventually meet Thalia and Luke, two demigods traveling to camp half-blood. The three bonded strongly, and Luke's passing, along with Thalia being temporarily changed into an pine treeevergreen, affected her greatly. She had a crush on Luke Castellan for some time but now is with Percy.
- Leo Valdez: A 15-year-old Greek demigod, he is the son of Hephaestus. He possesses the power over fire, a unique ability among the children of Hephaestus. He created the Argo II, using his skills with fire and machinery. He is part of the Second Great Prophecy and is a descendant of Sammy Valdez, Hazel's old boyfriend. He has a crush on Calypso. He swore on the River Styx that he will come back to her. Leo has a special connection to Gaia, who appeared to him as a child, and caused his mother's death. Many of the foes they face refer to him as "The Seventh Wheel" due to the fact he doesn't seem to fit in with the others - a topic he is aware of. He appears carefree and wisecracking, but, is shown to be quite insecure about his place among the others.
- Piper McLean: A 15-year-old Greek demigod, she is a daughter of Aphrodite. She can charmspeak (convince or persuade most people to do what she says). She carries a knife called Katropris, which used to belong to Helen of Troy, and shows her visions of the future. Although she is a tomboy, she is very beautiful and a knockout to boys, even though she tries to playdown her beauty. She is part of the Second Great Prophecy. She is dating Jason Grace, son of Jupiter, though she fears he may be taken from her by Reyna, his close Roman friend.
- Nico di Angelo: A Greek demigod, he is the only known son of Hades and the younger brother of the late Bianca di Angelo. Although he was born in Venice, Italy, in 1927, he is physically and developmentally 14. He and his sister were brought to the United States as young children by their mother, the daughter of an Italian diplomat. He still speaks Italian fluently. His mother was killed by Zeus, who was attempting to kill Bianca and Nico before they turned 16 because of the Great Prophecy (later fulfilled by Percy and Luke Castellan). Bianca and Nico spent the next 70 years in the Lotus Hotel before Hades had Alecto took them out and put them in a military school in Bar Harbor, Maine, hoping to have them fulfill the Great Prophecy. Nico's Roman half-sister is Hazel Levesque, a daughter of Hades' Roman counterpart Pluto, and is from Camp Jupiter. He has the power of necromancy and is one of the most powerful demigods currently living. In The Titan's Curse, he develops a grudge against Percy, thinking he purposely killed Bianca. Nico believes Percy was trying to kill him with some skeletons that followed him. In The Battle of the Labyrinth he learns to trust and not to hold grudges (the fatal flaw of most children of Hades) against people. He is the only demigod prior to the Heroes of Olympus series to have attended both Camp Half-Blood and Camp Jupiter, and was the first Greek to know about Camp Jupiter in The Son of Neptune. Nico briefly visits Camp Jupiter in The Son of Neptune, but pretends to not know Percy. After his visit, he attempts to locate and close the Doors of Death. In the process, he is pulled into Tartarus and nearly dies, which allows Gaia's forces to overwhelm him. He is briefly imprisoned in Epirus, before being transported to Rome by Ephialtes and Otis, who attempt to use him as bait for the other campers. They rescue him, and he later promises Percy to lead the others to Epirus in Greece, while Annabeth and Percy locate the entrance to the Doors of Death in Tartarus. In The House of Hades, he reveals that he, at one time, liked Percy Jackson.
- Thalia Grace: Chronologically 24, but physically and psychologically 15, Thalia is Jason's biological sister, but a daughter of Zeus rather than Jupiter. She was born on December 22. Thalia was almost killed when she was 12 after being revealed to be a child of one of the "Big Three" gods (Zeus, Poseidon, and Hades), and made a final stand against a group of hell hounds and the Three Furies on Half-Blood Hill to protect her companions, Annabeth Chase and Luke Castellan (who turned against the Gods in The Lightning Thief). Zeus takes pity upon his daughter and transforms her into a pine tree. After Luke poisons the tree in The Sea of Monsters, Annabeth, Percy, and Clarisse La Rue find and use the Golden Fleece to save the dying pine. The magic works too well, and Thalia is separated from the tree as a human, albeit slightly younger physically than her age would have been if she had aged normally. She later joins the Hunters of Artemis just before her birthday, becoming immortal while developmentally still 15, thereby making sure to escape the Great Prophecy.
- Tyson: Tyson is a half-brother of Percy by virtue of their father being Poseidon. In The Son of Neptune, Tyson, along with Percy's hell hound Mrs. O' Leary, is revealed to be searching for Percy. It appears that Tyson is the most successful at tracking Percy down and is nearly at Camp Jupiter before Percy leaves for his quest. He continues to track Percy and his friends north, but is always too late to reach them. Shortly after the attack on the Zhang mansion, Percy contacts him via a dream, telling him to locate the harpy Ella and escort her back to Camp Jupiter. Tyson, Ella and Mrs. O' Leary meet Percy just outside the camp, and it is implied that Tyson and Ella are in love with each other. Ella later chooses to follow Tyson rather than fly to safety, and Tyson aids the Romans in defeating the giant Polybotes' forces.
- Rachel Elizabeth Dare: Camp Half-Blood's oracle. She can predict the future, but it is recommended not to touch her when she is having an episode. She has frizzy red hair and always has a blue plastic hairbrush in her front pocket. Jason dreams about her and Grover having a "talk" with Reyna and Octavian. Before she became the oracle, she had a relationship with Percy, but she couldn't be married or have a boyfriend while being the oracle.
- Grover Underwood: Percy's best friend, who is a satyr. He and Percy have an empathy link, and they need to be careful or if one of them dies, both of them die. He has some skills in woodland magic and carries around a pair of pipes, just in case. He has curly brown hair and brown eye, and a furry hindquarters. His girlfriend is Juniper, who is a dryad, and cares for him very much.
- Jason Grace: A 16-year-old Roman son of Jupiter, he was born on July 1 (the Kalends of July, a day sacred to Juno). He can fly, control winds and lightning, and create storms. He is a natural leader and was praetor before Hera took his memory and sent him to Camp Half-Blood. He carries a sword as a weapon (given to him by Juno) as his first weapon, Ilvis, was destroyed. He is part of the Prophecy of Seven. His sister is Thalia Grace, daughter of Zeus. He is dating Piper McLean and has confirmed in the series that he has no feelings for Reyna, although Piper is still dubious of it. He is portrayed as very handsome, with combed blond hair and electric-blue eyes, just like Thalia. He is a major character in the great prophecy.
- Hazel Levesque: A Roman demigod, she is a daughter of Pluto and a voodoo priestess named Marie Levesque. Hazel has the ability to control precious metals and gems, has perfect bearings underground and can open new passages and tunnels underground. Lumps of precious metal and gemstones pop out of the ground around her, but bear a curse to whoever picks them up, and she tries to prevent people from doing so. She is African-American and was born on December 17, 1928. She is originally from New Orleans but, on her 13th birthday in 1941, she moved to Alaska, where she died with her mother a few months later in 1942 while standing up to the earth goddess Gaia. Nico di Angelo, her half brother, finds her in the Underworld 70 years later while looking for his dead sister, Bianca. Nico, feeling that Hazel needs a second chance, brings her back to life. She was 13 when she died and, when she returns, she is still 13 physically. Hazel is a part of the Prophecy of Seven. She is dating Frank Zhang, though Leo Valdez looks eerily like a boy named Sammy Valdez (Leo's great-grandfather) whom she used to date in New Orleans during her first life. If she had not died, she would have married him.
- Fai "Frank" Zhang: A 16-year-old Roman demigod with magical blood, he is a son of Mars and a descendant of Poseidon on his mother's side. He is descended from Periclymenus, son of Poseidon and Prince of Pylos. He is a Canadian from Vancouver, but has a vast ancestry coming from China, Rome, and Greece. His family's hometown is Li-Jien, or Legion. His last name, Zhang, means "master of bows." He possesses the power to shapeshift, an ability inherited from his ancestor Periclymenus. He is a part of the Prophecy of Seven. He is dating Hazel Levesque, daughter of Pluto. He is jealous of Leo because he believes Leo likes her, and Hazel has feelings for him because he's similar to Sammy. Frank's last hope for life relies on a piece of firewood (the Fire of Life, as it is called by Thanatos in The Son of Neptune) that holds him between life and death which he gives to Hazel Levesque to keep safe for him. This piece of wood is similar to Meleager's log.
- Reyna Avila Ramirez-Arellano: A 16-year-old Roman demigod and daughter of the Roman goddess of war, Bellona. She is one of the Roman praetors of Camp Jupiter. Percy Jackson says that she is a fighter. Her older sister is Hylla, Queen of the Amazons. Both Hylla and Reyna meet Percy Jackson in The Sea of Monsters. At first, they hate him for their encounter at Circe's island, but soon come to make amends. It is hinted that she dated Jason Grace, her first partner in praetorship, and has a crush on Percy Jackson, her previous partner in praetorship. She despises the camp's augur, Octavian. She has two metal dogs, Argentum and Aurum (Silver and Gold), both of which can tell when a person is lying. She is Puerto Rican, from San Juan, and hates to use her full name or have it be used by others, as she considers it a reminder of a painful childhood she has left behind.
- Octavian: Camp Jupiter's auger. He is very snooty and was doing anything possible to be the next praetor before Percy came to the camp. Instead of actual animals, he slices up stuffed animals, and snatches Percy's stuffed Panda bear, which Percy wasn't happy about. He is described as pale and skinny, with stringy blonde hair. Reyna (along with anyone who meets him) absolutely hate him because of how rude and stuck-up he is.
- "The Mark of Athena by Rick Riordan". Kirkus Reviews. October 9, 2012. Retrieved January 10, 2014.
- ""The Heroes Of Olympus: The Demigod Diaries" To Be Released This August". LeakyNews. 2012-01-01. Retrieved 2012-11-11.