GUESS WHO (round 19)

[tsunderes]

I happened to find a little scrap of paper in my desk with something scribbled on it. It seemed to be a clue to the author's identity, but I couldn't figure out who it was, even though they sounded really familiar! If you can figure who the character is, I'll give you 3 random cards, but only by 9/1. I mean, after a week, that's just too much effort. But here's what was written on that piece of paper:

"A serial killer mutilates my girlfriend, which causes a new personality to show."

Last round's mystery person was Matoi Tsunetsuki from Sayonara Zetsubou Sensei.