Fatal Flaws are mental or physical weaknesses that humans, demigods, and immortals possess. These flaws can often cause the downfall of the being, but are particularly dangerous to demigods. In Greek plays, they are often referred to as "Tragic Flaws".
The Siren's music has an oral hypnotic effect. When the Sirens sing, they sometimes reveal your fatal flaw. Flaws can produce an enticing image which is what lure sailors and adventurers to their deaths, either by drowning, being eaten by the Sirens, or by hitting the sharp rocks (and in modern times, mines) surrounding the island.
Known Fatal Flaws[]
Alive[]
Percy Jackson, whose fatal flaw, which is personal loyalty, affects the Great Prophecy.
Percy Jackson: His fatal flaw is excessive personal loyalty. He will risk his life (and even the world) for his friends, family, and sometimes even strangers and enemies with whom he empathizes (like when he warned enemy demigods that the Princess Andromeda was about to explode). Being overly loyal could lead to making you predictable to your enemies as well.
Annabeth Chase: Her fatal flaw is hubris, deadly pride. She thinks she can do anything better than everyone, even the gods, such as saving her family and building a brand new world exactly as she wanted (seen in The Sea of Monsters and The Battle of the Labyrinth). Annabeth says that many children of Athena share the same fatal flaw. In addition, her other fatal flaw is ambition. She desires power even though she knows she either doesn't need or can't have it.
Nico di Angelo: His fatal flaw is holding grudges. He will hold a grudge even if it costs him his own life. In The Battle of the Labyrinth, his deceased sister Bianca tells him that holding grudges is very dangerous for children of Hades.
Leo Valdez: His fatal flaw is a feeling of inferiority. He always feels like he's the least important; even in the team of seven demigods, he feels that he is the "seventh wheel." This causes him to sacrifice himself, though he is resurrected afterwards.
Drew Tanaka: Her fatal flaw is vanity, or excessive pride in one's appearance, qualities, abilities, and achievements. She shares this flaw among many other children of Aphrodite.
Hazel Levesque: Her fatal flaw was her past. This is shown by her flashbacks, and even though she ended up losing them, she still remembers her first life and treats it like her new life. For example, she treats Leo as if he were Sammy.
Frank Zhang: His fatal flaw was his low self-esteem. In Son of Neptune, he showed doubts of his own self-worth, which caused him to panic at the time he is needed. However, after the Blessing of Mars, these flaws seem to have faded slightly.
Piper McLean: Her fatal flaw is her low self-esteem. Being a daughter of a seemingly 'useless' love goddess, Aphrodite, she thinks herself as useless and invaluable. She feels so poor of herself that it causes her to get constantly bullied by kids from Wilderness School. But these flaws seem to have reduced after The House of Hades.
Mimi: Her fatal flaw is most likely wrath. She spent decades plotting revenge on Camp Jupiter for kicking her out of the legion due the uncontrollable foul odor she inherited from her divine mother, not caring about the lives she could have taken with her actions.
Deceased[]
Perseus: His fatal flaw was ambition. This was shown when he wanted to prove himself worthy of hospitality. He ended up promising that he would kill Medusa because of this, which gave rise to his near-impossible quest. Despite his actions, Perseus ended up living a happy life.
Odysseus: His fatal flaw was hubris. This was shown by his encounter with Polyphemus, when declared his true name after escaping the island, and by the statement that he won the Trojan War by himself, without any help from a god. Both of these brought the wrath of Poseidon upon him.
Theseus: His fatal flaw was impulsiveness/recklessness. He dumped Ariadne and acted rashly along with his friend Pirithous. He had the audacity to affront Hades, for which he was punished. Later, he fell out of favour from his subjects and died.
Bellerophon: His fatal flaw was hubris. He was too proud and attempted to force his way into Olympus. Zeus crippled him and the hero died slowly.
Otrera: Her fatal flaw was hubris. She was too proud and fought Dionysus, almost getting herself killed in the process.
Phaethon: His fatal flaw was his recklessness. As a result of being raised by his over-protective mother and sisters, he started to carelessly get himself in trouble. This flaw caused him to ride the Sun Chariot, ignoring his father Helios' advice, and leading to his own death.
Thomas Jefferson Jr.: Like all children of Tyr, T.J's fatal flaw was recklessness/inability to resist a challenge. This has lead to his death during the American Civil War and being baited into stabbing a stone giant in the heart.
Michael Varus: His fatal flaws were ambition and hubris. He showed ambition when he chose to journey to Alaska to solve the Prophecy of Seven and demonstrated the latter when ignoring the current augur's advice that the prophecy wasn't for him.
Luke Castellan: His fatal flaw was his excessive wrath. He was unable to forgive his father Hermes for what he had been through. Luke's anger blinded him so much that he went against his closest friends. By the time he realized it, it was too late and Luke ended up sacrificing himself.
Jason Grace: His fatal flaw was his temptation to deliberate. For years in Camp Jupiter, Jason always relied on careful choices, compromises, and hearing both sides of a debate. He never chose what he wanted. He never knew where he wanted to belong. Notus said that Jason reminds him of his own children, blown place to place, undecided, changing from day to day. Notus warned him that such hesitation could kill him one day.
Immortal[]
Pandora: Her fatal flaw is curiosity. When she was given the pithos from the gods, her curiosity made her open the pithos, which she was ordered not to, causing the world's destruction.
Hercules: His fatal flaw is his wrath. This flaw has led him to kill his own family, which caused him to the Twelve Labors. After that, he pushed an innocent boy off a cliff, causing him to work for the queen.
Arachne: Her fatal flaw is hubris, deadly pride. She thinks she can do anything (weaving, in her case) better than everyone else, even the gods. This resulted in Athena turning her into a monster.
Psyche: Her fatal flaw is low self-esteem. She didn't trust herself to make the right decisions and was tricked by her sisters to look upon Eros' true form. Despite her actions, Psyche was welcomed into godhood and got happily married.
Trivia[]
Hamartia is another word for a fatal flaw used mainly in the context of literature in reference to characters. It is a Greek word that means "missing the mark."
"Hamartia" is also the Greek word used in the Christian Bible commonly translated as "sin" in English.
They are often the same for demigod children of the same godly origin.
It is stated by Athena that the most dangerous flaws are those that are good in moderation in The Titan's Curse. In Percy's case, it is good to be loyal to your friends, but being overly loyal could lead to sacrificing Olympus or make you predictable to your enemies.
Of all the known Fatal Flaws, hubris is seen to be the most common throughout the series.
Hubris is a common fatal flaw for many characters in the Greek myths and beyond.
Thomas Jefferson Jr. is the only Norse demigod whose fatal flaw is known.
