In God of War III, Poseidon is the first major boss Kratos fights.
The battle occurs during the game’s opening assault on Mount Olympus. Kratos climbs toward the gods while supported by the Titans, and Poseidon confronts him in a large set piece involving the sea god, his hippocampi, and a colossal water form. Defeating Poseidon establishes the scale of Kratos's final Greek campaign.
Poseidon is one of the principal Olympian gods and rules the seas in Greek mythology. In the God of War series, he is also one of the gods who granted Kratos powers during the earlier games. His defeat contributes to the destruction spreading across Greece.
Poseidon is sometimes mistaken for the game’s final boss because the opening battle is unusually elaborate. The final confrontation in God of War III is against Zeus, not Poseidon.