50% Teacher 50% Assassin

A new teacher arrives in E Class and as they expected she's an assassin, but they don't know that straight away, sure they suspect it, but Hatsu Maki isn't an obvious Assassin. Though she has a large range of skills.

"Um...Hi! I'm your new teacher, you can call me Hatsu-Sensei and I'll be teaching Literature with Korosensei. I do hope you enjoy me as your teacher!"

Seemingly sweet and kind even Karma and Terasaka (and his gang) trust her. One of her many skills. She works hard, plays hard and kills hard.
Nobody has escaped her yet, and she isn't going to start now...but this assassin was once a teacher and a teacher's instincts call to her in this Assassination classroom. But is that all there is to it?