Kaede

Kaede first appears as a strict and rather serious and stoic woman however, she is downright sadistic and heartless as she would subject Mai-chan and the rest of her employees to constant sexual abuse and torture, she also quite disturbingly perverted as she would tell her victims dirty and vile things while abusing them as well as exposing herself to them when they are in pain. She seems to derive pleasure from the pain and torment caused by her onto Mai-chan, going so far as to masturbate at the sight of Mai-chan's mutilated body. She also has no problem witnessing a baby being blended into a milkshake as well killing those who displeased her including children.

Despite her irredeemable traits, she would eventually soften up to Mai-chan and develop feelings for her due to feeling a kindred spirit in her as she tolerated all the abuse and torture inflicted upon her. At last, Kaede would get what was coming to her, that is getting violently gang-raped. This moment brought out Kaede's humanity as she was put in Mai-chan's shoes briefly. Despite torturing and raping Mai-chan, she didn't want her to be subjected to a much worse fate by being a product of human experimentation, going so far as to betray her master and kill the president to protect her which shows that she does have her own set of morals.