Age Lift: Applies to the major characters in the film series; instead of being 12-13 in the first book, they are in their late teens in the first film.
The Beautiful Elite: Aphrodite's children especially, although it's implied that this applies to most, if not all, the demigods due to their divine heritage and the gods' propensity for attractive partners.
Gang of Hats: As stated below, each demigod shares some parental-domain-related power with their half-siblings - Aphrodite's children are all ridiculously gorgeous, Hephaestus's children are good with machinery, etcetera.
Green Thumb: Demeter's children. Dionysus' twins, too - they work best with grapes, but since their dad isn't allowed to touch anything vaguely related to wine, they settle for strawberries instead (just them walking among the strawberry fields makes them of better quality already.)
Heroic Bastards: The heroic demigods, anyway, since no one's godly and mortal parents are married.
Bastard Bastards: Played with in the evil demigods, most of them are fiercely loyal to their mortal parent but not to the rest of the Olympians, believing they mistreated their mortal parent.
Supreme Chef: Demeter's children; it's part of their mother's domain.
Teen Genius: Children of Athena and Hephaestus. Athena kids are wise and spend their time reading and researching, while Hephaestus kids are good with machinery.
Wrench Wench: Daughters of Hephaestus are just as good with mechanics as his sons.
You Can't Fight Fate: A running theme of the series, justifiable given its origins. However, prophecies being what they are, it's terribly easy to misinterpret one's fate.
Perseus "Percy" Jackson
"Is he dangerous?"
"Very, to his enemies."
The son of Poseidon, god of the sea, and clear-sighted mortal Sally Jackson. The titular hero of the series, the books start in Percy's sixth grade year when he kills one of the Furies, masquerading as his pre-algebra teacher. Has a Cool Sword, Anaklusmos ("Riptide") and later becomes the third person in history to bear the Curse of Achilles.Played by Logan Lerman in the film series.
Achilles' Heel: The small of his back. Or, in a more figurative sense, Annabeth..
Animal Talk: Can talk to horses and other vaguely equine beasts and sea creatures, since his dad made them.
Apocalypse Maiden: As a candidate for the one in the prophecy to make a decision that will either save or destroy Olympus, he's considered so dangerous that the gods even discuss whether or not to kill him to his face. Subverted when it turns out he isn't the one in the prophecy—Luke is.
Book Dumb: He prefers to leave the deep thinking to Annabeth. For example, when Franklin D. Roosevelt comes up in conversation, the only vaguely-related thing he can think of to say is "Like FDR Drive?"
Bully Hunter: Has a particular hatred for bullies, which he explicitly states in his narration in The Demigod Files.
Meaningful Name: Named after the only Greek hero to get a Happy Ending. It doesn't hurt that he slays Medusa (who's hacked-off head is used to get rid of his mother's husband, a "suitor") and hangs out with a pegasus.
Only Known By His Nickname: Virtually no one calls him Perseus, except for maybe the demon cheerleaders. Not even the big bad does. This is the reason he can tell monsters from normal people. They are the only ones to say "Perseus" when talking to him.
Showy Invincible Hero: Became this in the fifth book after the Curse of Achilles makes him near-immortal.
Skunk Stripe: In the third book, he gains a gray streak in his dark hair from having to hold up the sky. Curiously, this is never mentioned again.
Soft Water/Super Not-Drowning Skills: Not only can Percy always take a dive into water, from any height, to escape a bad situation (admit it, that's a handy thing to know), being submerged in water (more accurately, touching water in general, but it's strongest when he's submerged) heals and freshens him up, even to the point of detoxing any poison he's suffering from,; he doesn't even get wet unless he wants to. He can even use a lighter underwater. Being the son of the sea god has its perks.
The heroine of the series and the resident brainiac, Annabeth is the literal brainchild of Athena and military historian Frederick Chase (kids of Athena are just special that way). Her pastimes include architecture, Ancient Greek, killing monsters, and learning how to stab things. Annabeth ran away from home when she was seven and met up with Thalia and Luke; eventually they made their way to Camp Half-Blood, but lost Thalia in the process.Played by Alexandra Daddario in the film series.
Action Girl: Can kick a lot of ass, and is a more experienced warrior than Percy.
Fatal Flaw: Pride. Annabeth's problem is thinking that she can do anything, even when she can't, and, by extension, holding onto impossible goals. She thinks that she can solve every problem that she has, including that of her distant mother and traitorous friend. Because she thinks that she can fix these problems, she never really lets them go and moves on. This is why she takes the sky from Luke in Titan's Curse, despite it having 'bad idea' written all over it, among other things.
First Girl Wins: If you exclude Nancy Bobofit, who doesn't show up after the first few chapters, Annabeth is the first named girl Percy meets.
The Pollyanna: To some extent. She's well-aware that the world is not perfect, but it's her dream try to fix that, which is why she wants to be an architect. This is also shown with how she's convinced she can make Luke good again.
Why Did It Have To Be Spiders: Annabeth does not like spiders (explained by the story of Arachne) and the feeling is apparently mutual. Having to chase a mechanical spider through the Labyrinth was not her favorite thing ever.
Son of Hermes and May Castellan. When he was an infant, his mother tried to become the new host for the Oracle of Delphi. It went horribly wrong. May went crazyfrom visions of her son's eventual future and became The Ophelia, and spent Luke's childhood babbling at him about his horrible fate. He ran away and met up with Thalia and Annabeth; they eventually made it to Camp Half-Blood, but not before Thalia died. Luke went on a failed quest and came back with a scar.Played by Jake Abel in the film series.
The Ace: Good looking, charismatic, a good fighter, and his cabin's counselor.
Broken Ace: Too bad this hides extreme parental issues and resentment.
Woobie, Destroyer of Worlds: To the point when even the victims of his nefarious acts (Silena, Thalia, Annabeth) show compassion for him and want to help him. Even Percy, who out right resents him feels bad for the guy in the end.
Daughter of Ares and head counselor of Cabin Five, Clarisse frequently bullies new campers and her first appearance involves trying to shove Percy's head in a toilet. She and Percy never get along, but they do develop respect for one another.Played by Leven Rambin in the film series.
Achilles in His Tent: In a particularly brilliant History Repeats example, Clarisse refuses to let the Ares campers refuse to join the Battle for Manhattan because they believed they deserved a chariot they and the Apollo campers had been fighting over (which eventually went to the Apollo cabin). Just when they're on the losing side, Silena impersonates Clarisse and leads them into battle, getting killed in the process. Hence her subsequent Roaring Rampage of Revenge. Guess who did this before? Achilles, after his beloved best friend/cousin Patroclus's death.
Action Girl: She isn't the head counselor of the war god's cabin for nothing.
Adaptational Attractiveness: Percy doesn't describe her as particularly attractive in the books, while the graphic novel depicts her as something of a Brawn Hilda. In the film, she's played by Leven Rambin, best known for playing the stunningly beautiful Glimmer from The Hunger Games.
Badass: She killed a drakon to avenge Silena's death. What more needs to be said?
Who needs armor? She picks up a spear from her fallen comrade, and charges a 200 foot long drakon wearing a t-shirt and jeans.
Badass Boast: "I AM CLARISSE, DRAKON-SLAYER! I will kill you ALL!"
OOC Is Serious Business: In book 5, she is so angry at the Ares cabin being dissed that she and her cabin refuse to join the other demigods in defending Olympus. We repeat: Clarisse refused to join what could have possibly been the biggest and most monumental battle of her life.
Pet the Dog: Her concern for and friendship with Chris and Silena.
Red Oni, Blue Oni: She's the red oni any time she works with anyone else, period. Which is not often.
Son of Hermes and boyfriend of Clarisse. He's introduced as working on Luke's side and having gone insane when he went on a mission into the Labyrinth, but Dionysus heals him at the end of Battle of the Labyrinth.Played by Grey Damon in the film series.
Brother-Sister Incest: Averted in the case of his and Silena's relationship, considering the fact that in the fifth book, it is explained that gods do not have DNA, and thus makes any arguments against inter-camp relationships null and void; with the one exception of two people from the same cabin.
Fatal Family Photo: He just had to show off a picture of his girlfriend right before he raids the Princess Andromeda...
Daughter of Zeus and an eighties starlet with a poofy hairdo. Her birth broke the pact the Big Three had made after World War II to never have children again. She ran away from her alcoholic mother when she was younger, met up with Luke and eventually Annabeth, and made her way with them to Camp Half-Blood. There they were overwhelmed by monsters and Thalia stayed behind to hold them off, dying in the process. Zeus turned her body into a pine tree.Played by Paloma Kwiatkowski / Katelyn Mager (young) in the film series.
Abusive Parents: To say nothing of Zeus' abandonment, Thalia's mother was initially loving but then grew cold and distant, not to mention an alcoholic. The only reason Thalia didn't run away sooner was because of her younger brother Jason.
Acrophobic Bird: Kind of sucks that the daughter of lightning and the sky (which gives her wind and electricity powers) is scared of heights.
Apocalypse Maiden: Defied. Because she has the Fatal Flaw of being weak when offered power, like her father, she avoids being the demigod in the prophecy to make a choice that will save or destroy Olympus upon turning sixteen by becoming a Hunter and staying fifteen.
Archer Archetype: After she joins the Hunters of Artemis in book three, she grows into this while wielding a bow with arrows as her weapon, becoming calm, calculating, and a little distant.
Aloof Dark-Haired Girl: In contrast to blonde heroine Annabeth and Fiery Redhead Rachel, Thalia is sarcastic, slightly petty, and cold. She grows into this trope more when she becomes a Hunter, becoming much more mature.
Fatal Flaw: Holding grudges. Very subtly illustrated in her attitude towards her brother, Nico: she loves him dearly, because she's all he has in the world, but she also resents him because being all he has means she can't do anything for herself. And for bonus points, it's indirectly fatal. When she chose to join the Hunters and leave Nico at Camp Half-Blood, Zoe got the idea that she would be a good choice to groom as the next leader of the Hunters, and drags her along on the quest where she dies.
Really 80-something years old: Bianca and Nico were born in the 1930's, but he and his sister were put in the Lotus Hotel by their father. This kept them from aging until the Prophecy came up.
Apocalypse Maiden: Like Percy and Thalia, the idea that he could be the demigod of the Great Prophecy is considered, and Hades goes so far as to trick Nico into imprisoning Percy to ensure that Nico is the one.
Armoured Closet Gay: Acts cold, sinister, and withdrawn to prevent people from finding out he's in love with Percy.
Dark Is Not Evil: He's frequently described as creepy by someone who is four years older than him. Even Nico himself knows his personality, or just being the son of Hades, would make him an outcast. The fifth book gives him a well-deserved happy ending.
Ship Tease: Played with rather epically. He is depicted as being shy around Annabeth, which Percy interprets as him having feelings for her. Come House of Hades, we learn that he was actually jealous of her, as his true crush was on Percy Jackson himself. This is in restrospect quite visible in Nico's interactions with Percy in the original series, as he truly behaves as if having an infatuation with him.
Took a Level in Badass: Yes, the cute, excited little ten year old turns into one of the most badass characters in the series.
Troubled, but Cute: At first he's just an annoying cute little bro, then his sister dies. He stays cute.
The Unfavourite: Hades makes it blatantly obvious that he likes Bianca more than Nico.
Son of Nemesis, the goddess of revenge and balance, Ethan was one of the many residents of Cabin Eleven who went unclaimed or had no cabin of their own because their parents were minor gods. He promised his mother he would make a place on Olympus for the minor gods, and in exchange she took his eye.
Heel-Face Revolving Door: Starts out as a hero, then turns to Kronos's side, then turns back to being a hero again at the last second in The Last Olympian, resulting in his death.
Pride Before a Fall: His mother is the goddess that causes the "fall" part of this trope. Ethan himself follows in her footsteps.
Redemption Equals Death: In The Last Olympian, he changes sides at the last second when he realizes that Kronos doesn't build, only destroys, and tries to kill Kronos. Kronos, in turn, kills him for turning against him.
Stealth Pun: He is blind in one eye. His goal is to bring justice for the minor gods. You could say...justice is blind. (Or, in this case, half blind.)
A satyr and Percy's best friend, Grover is the Searcher sent to Yancy Academy to keep an eye on Percy. He leads Percy to Camp Half-Blood and joins him on each book's quest (except the second, where the object is to rescue him). His dream is to find the lost god of the wild, Pan. He eventually does. Just in time to watch Pan die.Played by Brandon T. Jackson in the film series.
Green Thumb: Melodies played on his reed pipes can make plants grow.
He's Just Hiding: In-universe, he does not believe Pan dead and his main motivation is to gain a Seeker's license so he can search for him. He's right, and he does find Pan...in time to see him actually die.
Herald: He's the one who reveals the existence of the mythical world to Percy.
Took a Level in Badass: Goes from being the unquestionable Butt Monkey in The Lightning Thief to being a competent member of the good guys' team whose skill set complements the more action-oriented demigods.
The Unfavourite: The Council of Cloven Elders has a very strong dislike for Grover out of all their satyrs, particularly after book four.
Introduced as Mr. Brunner, Percy's Latin teacher, Chiron is actually an immortal centaur keeping an eye on Percy. He serves as activities director of Camp Half-Blood and the Voice Of Reason.Played by Pierce Brosnan in the film adaptation of The Lightning Thiefand Anthony Head in The Sea of Monsters.
Tyson is first introduced as a school friend of Percy's, but he is later revealed to be a Cyclops - one-eyed children of Poseidon, therefore making him Percy's half-brother.Played by Douglas Smith in the film series.
The Ace: He sounds dumb sometimes, and he can be a bit of a crybaby, but he can do anything.
Berserk Button: Sort of. He never really seems to get angry (except at Polyphemus), but threatening harm to Percy or Annabeth is an excellent way to get him to squish you.
The Big Guy: Already the largest of Percy's main team, as a cyclops he has superhuman strength. Tyson's strength is considered extreme even for a cyclops though—he was able to defeat a fellow cyclops named Ma Gasket with two punches, and Ma Gasket was considered powerful for a cyclops herself. He was also able to bring down a Colchis bull with his bare hands and survive Kampe's poison. Being immune to both fire and water is just icing on the cake.
Cloudcuckoolander: He seems he's got a few screws loose, but actually has mad engineering skills.
Clingy Jealous Girl: Implied to be this in The Demigod Files, where Grover comments on the beauty of the tree nymphs up in Lake Placid, but then asks the interview to edit that part out so that Juniper won't kill him.
Beware the Nice Ones: Uses a shotgun to fend off a monster in The Last Olympian. This stretches back as far as The Lightning Thief, where it's heavily implied that she used Medusa's head to turn Gabe to stone.
Good Parents: Genuinely cares about her son's well-being, and shows it a lot.
Fainting Seer: As of becoming the mortal host for the Oracle of Delphi in The Last Olympian. She zones out and the spirit of the Oracle takes over her body, using it to recite prophecies. Lampshaded when Rachel worries about this happening in the middle of class.
Walking Spoiler: Almost everything about her in The Last Olympian is a spoiler.
Percy's abusive stepfather at the beginning of the series. He isn't the nicest of guys. By the end of The Lightning Thief, he's turned into a stone statue by Medusa's head. It's heavily implied that Sally used this on him.
Asshole Victim: Turning someone into stone from cold blood would have ordinary been a rather morally ambiguous act, but by the point it happens, he has proven himself such an asshole that you will at worst not care, at best cheer.
Bunny-Ears Lawyer: Many of the gods: Poseidon is one of the three most powerful gods in existence, and he walks around in a Hawaiian shirt and shorts; Dionysus likes playing Pac-Man and whines about being forbidden to drink wine and can only drink pop; and Apollo is the god of medicine, drives the sun chariot as a Maserati Spyder, and lets fifteen-year-old girls take it for a spin.
Jerkass Gods: Most of the gods at one point or another, but especially Zeus and Ares. Even the most sympathetically portrayed have their moments.
Mayfly-December Romance: With any demigod's mortal parent. The only major Olympians who do not have children are Hera, Hestia, and Artemis.
Dumb Muscle: While quite a competent tactician, Ares's pettiness and temper causes him to forgo strategy and use brute force in battle. His arrogance also causes him to underestimate his opponents. This is in contrast to Athena, goddess of tactical warfare.
The Friend Nobody Likes: Even his own family doesn't know why they put up with him, and he verges Nominal Hero status by being a god and not a Titan. The exception to this is his lover Aphrodite.
Jerkass: Ares is not that nice. He bullies his demigod children and picks fights with Percy every chance he gets.
The goddess of the moon, the hunt, and maidens. She is sworn as a perpetual maiden, and thus has no true children, but she does "adopt" maidens who foreswear men forever. Her main weapon in combat is a bow and quiver of arrows to use with it.Played by Ona Grauer in the film series.
Action Girl: Very good in combat, as expected of the goddess of the hunt.
Adaptation Dye-Job: It's stated she has auburn hair in the books, but is a brunette in the graphic novel.
Age Lift: In the movie, she appears as a full-grown woman instead of the young-girl form she assumes in the book.
Animorphism: Possibly. When Artemis is fighting against Atlas she is seen taking different animal forms at great speed by Percy. He then admits that another possibility could be that the pain of holding the sky is making him hallucinate and “see things.”
Not Bad: At the end of the The Titan's Curse she tells Percy that he didn't do bad, for a man. At first Percy thought it was an insult but then he realized that it was the first time she actually called him a man instead of a boy.
Straw Feminist: Subverted; Percy does note how ridiculously radical she and her hunters are, but Artemis is also a goddess and hero who also can be very nice, and is not nearly as misandrist as Percy makes out at first.
Genius Bruiser: She is the goddess of both wisdom and battle strategy, and in classical mythology is one of more powerful gods, next to Zeus and Poseidon. Percy himself points out that Athena would be a worse enemy to have than even Dionysus or Ares, because if she planned to have you killed, then you would die. No matter what.
If You Ever Do Anything to Hurt Her...: Invoked by Athena towards Percy in regards to his friendship with Annabeth. As stated above, Athena would be the worst enemy to have amongst the gods. If she wanted you dead, then you would be dead, no matter how hard you would try to evade her.
Lady of War: One of the oldest ones in the book, she's calm and solemn but also very capable of kicking your ass.
Overprotective Mom: Well, as "overprotective" as any of the absentee parent gods can get, anyway, but she's shown not to particularly like the idea of Percy being with her daughter.
The Strategist: Tactical warfare is part of her domain, so she fulfills this role among the Olympians.
Goddess of the harvest and Persephone's mother.
Demoted to Extra: From the original mythology, at least; she only gets an appearance in the winter solstice in the first book, a scene with her daughter and Hades in The Last Olympian, and a few appearances in battle.
Green Thumb: Plants are part of her domain. In the last book she turns an entire army into a wheat field.
Obnoxious In-Laws: Manages to be this to her brother Hades regarding him and Persephone, criticizing Hades' work and wishing Persephone could have married someone with a more respectable domain.
The god of wine, parties, and insanity. He's being "punished" by being assigned as the head of Camp Half-Blood for 100 years after chasing after an off-limits nymph, and is grouchy due to being put off the bottle and thus can't drink until his punishment is over. Has an extremely strong dislike of heroes. Known as "Mr. D" to the campers.Played by Luke Camilleri in the film adaptation of The Lightning Thief, andStanley Tucci in The Sea of Monsters.
Accidental Misnaming: Mr. D staunchly refuses to get any of the campers' names right. Just ask Peter Johnson.
The Alcoholic: Although he's forbidden to touch anything wine-related for the next century, much to his annoyance.
Big Damn Heroes: In The Titan's Curse, saving Percy, Thalia, Zoë, and Grover from Dr. Thorn and his soldiers.
Demoted to Extra: In the film series, his punishment doesn't seem to be in effect, and as such Chiron seems to be camp director instead of him. He only has a cameo appearance at the Olympian council.
Freudian Excuse: A non-villainous example. The reason he dislikes demigod heroes is because his wife Ariadne was abandoned by the demigod Theseus.
Jerk with a Heart of Gold: Often comes across as mean and uncaring, but he genuinely cares about the protagonists and comes to their aid in one crucial moment.
Mind Rape: His signature move, being the god of insanity. He does say that the insanity he put on Thorn's soldiers was temporary, but it is scary.
Papa Wolf: Minor example, but he contacts Percy in a dream to make sure his one remaining son is safe.
Pet the Dog: Restoring Chris Rodriguez' sanity in The Battle of the Labyrinth.
The Other Darrin: Played by Luke Camilleri in the first film and Stanley Tucci in the second. Justified in-universe due to all the gods being able to change their appearance.
The god of the underworld. Bitter and asocial, but not truly evil.Played by Steve Coogan in the film series.
Animal Motifs: He is described as been similar to a panther: lithe, graceful and dangerous.
Authority Equals Asskicking: In “The Lighting Thief” upon Percy’s meeting with Hades he states that Hades, above Ares and Dionysus, radiated power and that he had an air of order and lordship. The Asskicking part is seen in his Big Damn Heroes moment in “The Last Olympian”
Big Bad: Is set up as this for most of the first book, though it's eventually revealed he actually had nothing to do with the theft of the lightning bolt.
I Gave My Word: The only one of the Big Three to take the vow of no children seriously. Or at least more serious than the other two. Zeus being Zeus will screw anything at the drop of a hat, and Poseidon hinted at having many more children than just Percy. Hades' last set of children were born in the 1920s and his lover got nuked because of it. He had no children since.
Papa Wolf: Hades, it seems, is willing to go to much further lengths to protect his children than his brothers, including visiting them in person. Plus, it's stated that Nico lives in the Underworld with him.
Parental Favoritism: Hades makes it quite clear that he'd rather have Bianca alive instead of Nico, though it's probably because of Bianca's resemblance to their mother.
Parental Favoritism: She flung Hephaestus off of Olympus for having the audacity to be born less than beautiful, and makes it painfully obvious that she dislikes those demigods born to already-married gods and goddesses.
The goddess of the hearth. She's often overlooked by the other characters, often quite literally.
Ascended Extra: Plays a far more important role in The Last Olympian than she does in the original mythology.
Demoted to Extra: In the original mythology, and of course as part of her past in the books. She seems to have happily embraced the option.
Chekhov's Gunman: The little girl tending the hearth as Percy tours the camp for the first time in The Lightning Thief appears four books later as Hestia, goddess of the hearth and the titular last Olympian.
He's Just Hiding: In-universe, Grover does not believe Pan dead and his main motivation throughout the series is to gain a Seeker's license so he can find Pan.
Magic Music: Music played on his reed pipes can make plants grow.
Goddess of springtime, Demeter's daughter, and Queen of the Underworld. Married to Hades.
Clingy Jealous Girl: A milder example than Hera, but she doesn't like it when Maria di Angelo is brought up. note Actually a carry-over from the original mythology, where she turns Hades's ex-mistress into a the first mint plant.
Lady Macbeth: Goes behind Hades' back to try and ensure he's just as powerful as Zeus and Poseidon. One of the reasons Nico decides to spend more time in the Underworld is so that he can counteract Persephone's influence.
Wicked Stepmother: To Nico with whom she has a very strained relationship. She apparently turned him into a dandelion at one point.
Woman in White: While in the Underworld and Hades's queen; she wears a washed-out white dress. When she's out of it, her attire is very colorful.
The god of the oceans, storms, earthquakes and horses. Poseidon is shown to take greater care of his children than other gods and is more mature than his brother Zeus.Played by Kevin Mc Kidd in the film series.
Doting Parent: As doting as an absentee god parent can be, anyway. But he's especially this for Percy in comparison to some of the other gods, especially Zeus and Hades.
Father Neptune: The Greek equivalent of the Trope Namer. Especially apparent while fighting against Oceanus in The Last Olympian.
Immortal Immaturity: Averted. In ancient times he was very similar to Zeus in temperament. He would often hold grudges and be highly vindictive when things did not go his way. In the series he comes across as having matured to a degree where he is much more reasonable, at least compare to his brother.
Lord of Olympus and god of storms, justice, and oaths. The last two being ironic considering his actions throughout the series.Played by Sean Bean in the film series.
Bolt of Divine Retribution: Quite literally. His symbol of power is the "master bolt." The first lightning bolt and most powerful weapon in the series.
Immortal Immaturity: In ancient times, Zeus and Poseidon had almost interchangeable personalities. By modern day, Poseidon has matured to a degree, so he tends to be more reasonable. Zeus has not and still comes across as a pompous git who thinks he is perfect.
I Reject Your Reality: Zeus tries to deny the return of the Titans until he is presented with irrefutable evidence but by then it is too late to do anything. He denies the return of the Giants as well and that the Olympians need demigod help to stop them. Hera states in The Heroes of Olympus that Zeus has a long history of this thanks to his pride.
Jerkass: All the gods are this to a degree, but Zeus stands out compared to the others.
Karma Houdini: Despite breaking a sacred oath and pulling a ton of other crap Zeus is never held accountable for his actions. Instead his children often have to pay for his crimes and mistakes. Being the most powerful god around has its perks.
And I Must Scream: He literally cannot die. The first time, he was chopped into bits and pitched into Tartarus. The second time, his consciousness exploded and was spread so thinly across the world that there's little hope of it reassembling.
Asskicking Equals Authority: Became King of the Titans through being the most powerful, being the one who killed his father in the original mythology.
Batman Gambit: Allowing the Fleece to be returned to Camp Half-Blood so Thalia could be brought back to life, and he could count on her Fatal Flaw to sway her to his side so he could have a chance to control the Great Prophecy. It fails.
Big Bad: Of the entire series. His goal is to be resurrected, and the demigods and gods have to stop him because it would mean the fall of civilization.
Big "NO!": Lets one lose when he's finally defeated.
The Chessmaster: Manipulates people and events to further his goal of reforming and taking over the world.
Sadistic Choice: In the fifth book, Kronos frequently threatens to kill Percy's friends unless he surrenders to him.
Sealed Evil in a Can: Initially, his remains are just in a particularly creepy sarcophagus that gets stronger every time a demigod forsakes the Olympians and joins his side. Later, Luke graduates to being his Soul Jar.
Time Master: Despite this not being strictly accurate (Chronos, the god of time, was an entirely different entity), Kronos and Chronos being one and the same has been Fanon since the Ancients. (See the other Wiki for a detailed account on the theme.)
A huntress of the goddess Artemis and her former lieutenant. One of Atlas's daughters, who was disowned by her family after helping Hercules steal from their apple tree. She is replaced by Thalia Grace after her death and turned into a constellation called "The Huntress" by Artemis.
Action Girl: Artemis's second-in-command, and thus good in battle.
Does Not Like Men: But is perfectly capable of liking and befriending them, once they earn more than the barest token respect.
I Have No Daughter: Her family pulled this on her for helping Hercules steal from their apple tree.
Jerk with a Heart of Gold: In her debut, she comes off as snobby, aloof, and hostile, particularly to Percy. However, over the quest, she starts showing a more caring side, and becomes more sympathetic once her backstory is revealed.
"The last boy to see this camp... when was it, Zoe?"
"That boy in Colorado. You turned him into a jackalope."
"Ah, yes. I enjoy making jackalopes."
Apparently the last time the Hunters were at Camp Half-Blood, it burned down. Zoe blames the half-bloods.
Not So Stoic: Very cold and professional, but it's strongly implied she only acts that way because she's not comfortable around half-bloods; we see signs of Zoe having a very active sense of humor and warmth as she relaxes around the quest group, and it's likely that when she's around just the Hunters, that side of her is much more prominent.
Secretly Dying: Knew from the start that going on the quest was a death sentence for her, but went anyway out of loyalty to her beloved Artemis.
Stars Are Souls: She's turned into a constellation, "The Huntress", after she dies.
Straw Feminist: At first appears to be this, but is justified/deconstructed when Riordan reveals a Freudian Excuse for her hating males, and eventually portrays her beliefs in a less radical and ludicrous style. It's not that she hates men, she just doesn't trust heroes because too many of them have betrayed her or turned on the Hunters in the past.
Undying Loyalty: To Artemis, so much that she went on a quest she knew would kill her just to save her.
A sorceress who rules a island where she turns men into pigs.
Really 700 Years Old: She appears to be fifteen or sixteen, although she's been around for millenia.
Unrequited Tragic Maiden: A variation. She's doomed to always fall in love with the hero who washes up on her island, but never have her affections returned. In a particularly cruel twist, the heroes cannot leave Ogygia until she falls for them.
What Could Have Been: In-universe. After turning down her offer to stay with her on the island, Percy wonders what would have happened if he'd accepted it. His narration even calls her his biggest what-if.
Woman in White: Mysterious, beautiful, and wears a sleeveless white Greek dress.
Son of Athena and inventor of the Labyrinth. He's also Quintus, a temporary swordsman trainer at Camp Half-Blood.
Actually, I Am Him: Pulls this near the end of Battle of the Labyrinthwhen revealing that he and Quintus are the same person.
The Aloner: Is a rather lonely person in general, and claims to work only for himself.
Dirty Coward: Tends to run and hide from his problems rather than face them.
Heroic Sacrifice: Dies to get the Labyrinth, which is tied to his life force, to collapse, and save Camp Half-Blood.
Meaningful Name: Quintus means "fifth" in Latin, and it's the name for his fifth body.
What the Hell, Hero?: Athena pulls this on him when he tricks Perdix into falling off a balcony. To be specific, she turns Perdix into a partridge and then brands him with a mark of said partridge, which would never fade.
Also gets called out by Annabeth, who tells him that Athena's children are supposed to be wise, not just clever. He realizes she's right, leading to his Heroic Sacrifice and his entrusting of his laptop to her.
A child of Gaia and Tartarus. He was created to avenge the defeat of the Titans, but was defeated and imprisoned in Tartarus. Released in modern times by Percy on accident. He once again tries to destroy the gods and serves as a distraction for Kronos.
The Dreaded: Feared by the Olympians more than any other threat.
Eldritch Abomination: More so than anyone else. His body is constantly shifting between every type of monster and new ones and looking at him for too long would drive a demigod insane.