Mana  

, 真魚

Yuta's eternal companion is a woman who was raised by a group of elderly women in a hut. These women were actually mermaids who intended to consume Mana when she reached adulthood, in order to restore their youth. Despite her naivety and spoiled upbringing, Mana has strong feelings for Yuta and is fiercely loyal to him. However, it's unclear whether these emotions are genuine love or simply affection.