Tachibana Aina

She is a former mermaid princess who was forced to live on land after becoming "tainted".
She is also a member of the mermaid family that Utsumi Hinowa enshrines in her home.

Hinowa lives with her as her caretaker, and the two have become close friends, transcending race and status.

While she enjoys her life on land, she especially cherishes the bonds of friendship she has formed with her newfound friends.