Ryuen from Class C mentions how she is still acting as the "Queen" of the school for being in Class A. There is an intense rivalry between her and Ryuen alongside their respective classes as she thinks his challenges against Class A are interesting but ultimately futile. In volume 5 of the light novel, she was revealed to know about the "White Room" and cryptically reveals that she knows Kiyotaka, where she met him 8 years and 243 days ago in the past. According to her, she knows him very well and everything about his mysterious past though he denied knowledge of her and doesn't seem to remember her.