Umi no Triton
海のトリトン
5000 years ago, the Triton Family was living peacefully in Atlantis until the Poseidon Family destroyed them all out of jealousy for their successes. The race of merman was annihilated leaving Triton, the last survivor of his kind. Ruka took the orphaned Triton to Japan in order to protect him from his enemies.
(Source: Wikipedia)