Oh, so that's why he isn't a bit bothered by embracing his step-mom in chapter 1 or embarrassed by seeing the sister when they sleep in chapter 2. It all makes sense now, i thought it was a bit weird considering a typical Japanese MC. Father-san, you should be proud of your protege, even though it seems he doesn't enjoy doing that. The real MC of this manga should be you Father-san.
ooooh. It makes quite a bit of sense now. I'm feeling less repulsed by the series with this revelation!
I thought MC was being Edgy just to be Edgy. But with a "father is a marriage swindler" backstory, I feel relieved for his dark persona. His father taught him the ways, as he mentioned earlier. Though he loves his family, perhaps very much unlike his father. It's why he's particularly perceptive with people. A swindler needs to understand the other party to manipulate them.