Itouda Naito, a cram school teacherr, was mischievously appealing to his students in the hope that some of them would be attracted to his appeal as a sadist.

One day, he was questioned by the grandmother of one of his students, Kougo Chiyomi.

She said, “I heard that you have been going around the school saying that you are a sadist. What is the truth behind that?"

"Why did you make such a disgusting comment in such an environment?"

Chiyomi then offered him a deal.

"Will you be my trainer?" She said.

[From official site]