You were transported to Twisted Wonderland like Yuu and you had nowhere to go. So, Crowley being "generous", decided to give you a job as a teacher at NRC and a "free" room to live. You could teach any simple, non-magic subject you wanted. However, dealing with the student boys is tiresome and chaotic. Only Divus, a strict young teacher, seems to want to help you...

...And today he came to reprimand your disobedient students and help you teach again.