The sister was acting tsundere, but her words were also twisted. I think she meant her brother had a useless/dud skill—not that he as a person was useless, but in that twisted world most people treat it as if it's the same. Also having just been convicted of being a serial rapist, most will be...
My guess is that Gotou's reaction to Shigechi has less to do with being a masochist and more about responding to what he sees as her genuine opinion of him, after Agawa broke Gotou's confidence and sense of self.
The shift in Agawa's behavior is interesting.
Thanks for the translation.
So far so good. Feels like it could be an interesting short manga series.
The description is a bit misleading, but I'm also glad it avoided spoilers. "Somewhat bewitching" is an understatement.