Ibitsu (OKADA Kazuto)

There is something a bit twisted inside of the teenage girl Madoka. It comes out one day when she has to deal with a groper on a public train. He may be scarred for life by the time she's finally through with him but for her, at least, this encounter may only be the beginning.

Alternative note: If you are a male sub or a Female Dom, then this manga might be to your liking. If you're a Male Dom, then go read Nana to Kaoru instead of this. Nana to Kaoru is a much happier Dom/sub romance manga, whereas Ibitsu turns dark toward the end chapters.