God of the sea, earthquakes, and horses. Percy Jackson's father. One of the Big Three who swore not to father children after World War II. His relationship with Percy is defined by distance and periodic, costly interventions.

Goddess of wisdom, craft, and battle strategy. Annabeth Chase's mother. Born fully formed from Zeus's head. Her relationship with Poseidon is a persistent hostility that complicates Percy and Annabeth's relationship.

King of the Olympians, god of the sky and thunder. Thalia and Jason Grace's father. His paranoia about the Great Prophecy drives much of the plot of the original series. Authoritative, proud, and not above holding grudges for millennia.

God of the Underworld and king of the dead. Nico and Bianca di Angelo's father. Perpetually aggrieved at his exclusion from Olympus politics, but not actually evil - one of the series' recurring jokes is that Hades is treated as a villain when he usually isn't.

God of war and Clarisse's father. Cruel, belligerent, and happy to stir up conflict for its own sake. Acts as a secondary antagonist in The Lightning Thief before becoming a more complex recurring presence.

God of travelers, thieves, and messengers. Luke Castellan's father, whose neglect of his son is a key driver of the original series' plot. One of the more sympathetic Olympians - he knows what his inattention has cost.

Goddess of the hunt and the moon. Leader of the Hunters of Artemis, an immortal band of young women who swear off romantic love in exchange for eternal life. One of the few Olympians who treats demigods with consistent respect.

God of the sun, music, poetry, and prophecy. Protagonist of the Trials of Apollo series in which Zeus strips him of his godhood and sends him to earth as the awkward mortal teenager Lester Papadopoulos. His arc across five books is a genuine redemption story - he begins as an insufferable narcissist and earns his way back to godhood by learning what it costs to actually care about someone.

God of wine, madness, and parties, serving as the reluctant director of Camp Half-Blood as punishment from Zeus. Perpetually aggrieved, consistently unhelpful, and occasionally crucial. One of the series' best comic characters.