Yoku Shioya as Triton

Taken in as a baby by the human boy, Kazuya, Triton is raised on land and gets to know human society. However, Triton decides to return to the sea with his dolphin friends in order to get revenge on the Poseidon family for killing all the mermen and mermaids of his family.

With his dolphin friends Ruka, Uru, Karu, and Fin, he proceeds on a one-man war against the Poseidon family. During his journey, Triton meets Pipiko, the last surviving mermaid. Together, they work together to stop Poseidon and his evil minions and get vengeance for their family.