* His mother, Sally Jackson, is the descendant of the Greek Goddess Hecate: This explains why she has a strong connection to magic and why she's able to protect Percy from monsters.
* His father, Poseidon, is the God of the Sea: This confirms Percy's suspicions and explains his powers and connection to water.
* He has a half-brother named Tyson, who is a Cyclops: Tyson is initially presented as a monster, but Percy eventually learns that he is his half-brother and a good friend.
* He has a half-sister, Thalia Grace, who is a hunter of Artemis: Thalia was thought to be dead, but she's actually alive and a Hunter of Artemis, a group of immortal women dedicated to the goddess of the hunt.
These revelations significantly impact Percy's understanding of his identity and his place in the world. He grapples with the implications of being the son of a god and the responsibility that comes with it. He also forms a strong bond with his siblings, who are all dealing with their own struggles and challenges.