Really enjoying this manga - I'm just hoping they don't follow the same route as many horror manga seems to be doing. MC kills all of their bullies... so then they randomly add several more "bullies" for the MC to kill and keep dragging it on that way...
sound like the step-dad did truly love her mom, which make me wonder why he didn't just go and murder the one killed her instead of just put it all on Shizuku.
They kinda "hinted" at this, basically he "lost his mind" and started to see his step-daughter as his wife but he also hated her as he blamed her for his wifes death. So he would attack and r*** her - taking revenge and "filling the void" of his dead wife. Even the MC recognised that things would have been different if her mum didn't die and that they were a happy family - also why she was willing to "forgive him" to an extent.
He also probably knew he couldn't just kill that dude as he was the politicians' son, annnnnd he probably felt "responsible" for "caring" (I use that very loosely) for his dead wifes daughter - hence why she still lives with him and he hasn't thrown her out or whatever.
It's a shame she gave him a "decent" death but I guess it's whats best to help her not be held responsible for the crime of the other dude and shit.