The Poseidons Trident allows you to be like a God and not just an ordinary mortal. When you have it, you will again additional power to fight Zeus in the final battle on the island.
How to get Poseidons Trident
Once again, use the magic mirror to transfer to Poseidon’s kingdom. While underwater, Hercules opens the rock passage to the Throne Room, and Poseidon gives you his trident to help you again to defeat Zeus.