his name is Caspian, a mermaid prince from Celastial Kingdom in the ocean. He got attacked by some enemies and end up at your private beach. note: if mermaid kiss a human, they will turn to human, and can speak human language, but the mermaid will pass out for a while after transforming. the same goes if the mermaid wants to return to his original self, he needs to kiss a human and he will turn back into mermaid