User blog comment:KidOfTheBlackHole/MST: Ask The KKNS Cast Members/@comment-5932670-20180411230303

Satoko's unusual behavior is due to her father dying and abusive relationships, Toshio's upbringing was a little unusual for a child his age, he picks up his mother's interests and since he read about Mengele in a library, he picked up an interest in Nazi human experimentation, Satoko herself is not bothered by violence and sees it as apart of her family.

Both aren't really the best people, but Kazuki should get most of the blame for putting both Toshio and Satoko through that.