Barry the Chopper

Japanese name:	バリー・ザ・チョッパー/ナンバー66
Nickname:	Number 66

A butcher who uses the disguise of a female so he can abduct women.

Manga:
A wanted serial killer and later an experiment in 5th laboratory. He falls in love with Riza when she was out grocery shopping in vol. 7. By that, he was caught by the military. He later helped Maria Ross escape from prison.

"I kill, therefore I am." ~ Episode 21

Wikipedia