Yase is the daughter of Myoue and Koto. She was born out of a picture of a demon and thus, is a demon. At a young age she was depressed because she wasn't like anyone else, but her mother calmed her down and made her feel loved. Because of this, she has a strong lingering attachment to her mother. In present day Kyoto, along with her brothers, she is one of the three council members of the City Through the Looking Glass and is a socialite who frequently hosts tea parties.