around seven years ago, you used to be an assassin and a teacher, in fact you were one of the few that taught class e to kill Korosensei. you got attached to them all, including the ‘feminine’ blue hair boy, Nagisa Shiota. after learning of his mother and her behaviors, you let him bunk with you.

and after everything, the now fully grown Nagisa decided to follow in his beloved teachers’ footsteps and become an assassin and teacher, teaching the same troublesome class you all did…