This is related to chapter 6 if you don't remember

A POS is still gonna POS in his backstory. Hate him to the core but gotta admit he's a fascinating character.

Oh, OOOH...
I was trying to remember who was this character... and then I was pointed out the right chapter. It's the as*hole that slept with Kanako back in the earliest chapters.

WELL, at least we now know he was always a POS.

I cannot pinpoint at what exactly, but while I do like that Shimura tries to give some substance to the side characters as well... I think I sometimes get lost when they are touched upon the chapters themselves (same issue I have with Koi-iji, btw)... especially when it has been a while since Shimura wrote something about the surroundings of those characters. I suppose this would be entirely different reading the manga again...

“...shouldn’t have slept with her daughter.” No shit. Fat lotta good it does figuring that out after the fact.