Poseidon

Poseidon is one of the Big Three in Greek Mythology, the god of the ocean. In this case, Zeus is trying to overthrow Poseidon and Hades and take ultimate power. Poseidon will give you his trident, which will aid you in battle with Zeus. To reach him, you must dive under the ocean and swim to a stone barrier (or teleport using the mirror Aphrodite gave you). Hercules, once you get his help, will help you break through the barrier. To open passage farther, you must get a starfish located in the museum on Mythology Island. Then you will come to Poseidon, who will give you his trident. The trident allows you to grow huge (god-size).