Mana

An immortal companion of Yuta. She was raised by a group of old women that kept her captive and incapacitated in a hut. They were really mermaids that sought to eat Mana once she reached her adolescence to regain their youth. She travels with Yuta since, and possesses a large sense of loyalty and feelings towards him, but due to her somewhat naive and spoiled nature, she doesn't seem to truly realize that her emotions towards him are possibly love or just simple affection.