Kazanashi Toa

She is a second-year student at St. Orkis Academy. She is a sex slave of Kei (the main character) and an assistant to help him in training. She has a fake background and transferred to the academy ahead of Kei. She is absolutely obedient to Kei, but sometimes makes light talk and begs for training. She usually gives the impression of being friendly, but she is a true slave who faithfully obeys Kei's orders, no matter how lewd they may be.

Translated from the official site