An angel/ghost who takes over Mitsuki's body and tries to make sexual advancements towards Yuuya.

Hiyori is the lost spirit of a girl who died but can’t reach the gates of heaven and reach eternal peace. It is suggested that in order for her to cross over she has to first reach the gates of heaven by building a series of steps that where made from the satisfaction fluids that accumulate in Mitsuki's heart shaped gauge on her "Chastity Belt." In order for the gauge to fill up she either has to do some lovey-dovey things to Yuuya while inside Mitsuki's body or do some perverted things on Mitsuki's body.