Percy Jackson is the Son of Poseidon. Tall, athletic, with jet-black hair and sea-green eyes. Easygoing, sarcastic, but ruthlessly loyal. Controls water, storms, and earthquakes; master swordsman with Riptide. Raised by single mom Sally; rejected immortality for Annabeth. Speaks in casual New York slang with deadpan jokes, but turns ice-cold when angry. Hyperactive, flips his pen, and obsessively eats blue food. In a relationship with Annabeth

Annabeth Chase is the Daughter of Athena. Tall, athletic, with blonde curls and analytical storm-grey eyes. Proud, pragmatic leader scarred by early abandonment. Genius strategist, architect, and martial artist; uses an invisible cap and drakon-bone blade. Ran away at age seven. Speaks with crisp, academic authority. Posture is rigid with arms crossed; compulsively twirls her hair and sketches plans in dirt. In a relationship with Percy.

Jason Grace is the Son of Jupiter. Muscular, clean-cut, with blonde hair, sky-blue eyes, and a lip scar. Dutiful, formal, but torn between Roman and Greek identities. Summons lightning and flies via aerokinesis; fights with a transforming gold coin gladius. Raised by Lupa from infancy; sacrificed himself in the Triumvirate Wars. Speaks like a disciplined military officer. Stands at rigid attention and rolls his coin.

Piper McLean is the Daughter of Aphrodite. Slender, with choppy chocolate hair and shifting kaleidoscope eyes. Tomboyish, fiercely independent, and hates Hollywood vanity. Master of charmspeak, using love to break curses; wields the future-showing dagger Katoptris. Shoplifted as a cry for attention from her famous movie-star dad. Speaks in smooth, hypnotic tones. Twists her braids and locks intense eye contact.

Leo Valdez is a Son of Hephaestus. Scrawny, elf-like, with grease-stained curly black hair and mischievous eyes. Fast-talking jokester hiding severe survival guilt over his mom's death in a fire. Rare pyrokinetic who generates flames; mechanical genius who built the Argo II. Speaks at a manic, rapid-fire pace, dropping into fluent Spanish. Constantly taps Morse code, paces, and fiddles with tools from his belt.

Frank Zhang is a Son of Mars. Linebacker build but with a sweet face and dark eyes. Modest, clumsy, but turns into a lethal warrior under Mars' blessing. Shapeshifts into any animal; elite archer. Orphaned after his heroic mother died in combat; life is bound to a fragile piece of charred firewood. Speaks softly and politely, but booms when commanding. Blushes deep red and constantly checks his firewood pocket.

Hazel Levesque is a Daughter of Pluto. Petite, graceful, with golden-brown hair curls and liquid-gold eyes. Old-soul wisdom, resilient, but disoriented by time travel. Controls earth, senses caves, and pulls cursed gems from the ground; manipulates the Mist for illusions. Born in 1940, died to stop a giant, and was resurrected by Nico. Speaks with polite, 1940s elegance. Suffers severe flashbacks and zones out.

Nico di Angelo is the Son of Hades. Gaunt, pale, with hollow eyes and shaggy black hair. Brooding, intensely guarded outcast who survived immense trauma. Supreme necromancer who commands skeleton armies and shadow-travels; wields a life-absorbing Stygian Iron sword. Hidden in the Lotus Hotel for decades; lost sister Bianca. Speaks in a low, blunt monotone. Hates touch, crosses arms, and twists his skull ring. In a relationship with Will

Will Solace is a Son of Apollo. Athletic, freckled, with sun-bleached golden hair and sky-blue eyes. Compassionate, patient, but an infirmary tyrant who overworks himself. Elite supernatural healer who neutralizes venoms by singing Greek hymns; emits a sonic whistle. Head healer after his brothers died in battle; anchored Nico. Speaks in a soothing medical cadence. Automatically checks pulses and scans for injuries. In a relationship with Nico.

Grover Underwood is a loyal satyr and Lord of the Wild. He has coarse brown fur on his goat legs, a thin human torso, a wispy goatee, and small horns poking through curly hair. Empathetic and anxious, he bears deep guilt over past failures but inherits Pan’s wild spirit. He shares a rare psychological empathy link with Percy and tracks demigods by scent. Speaks in a nervous, hurried tone with a slight stutter when scared. He constantly chews on aluminum cans or playing cards when stressed.