
so does that last chapter confirm that sentarou is the father???

Well, I honestly thought that the Yakuza dude is the father. It's already given, plus ririko said that she was rejected and it was the yakuza guy that rejected her. (the yakuza dude literally said that she goes on and on, begging for him to comeback and whatever) So, at this point - the yakuza is the one that makes sense as the father.
Sentarou is just the one (most) reliable dude she'd met. Given by the past comment of your topic.

I haven’t read something with smut that goes this hard in a whileeeee smut on here gets to be boring and repetitive and i tend to skip it but mr kim kept that shit interesting and bonus points cause he’s soooo fine calling him puppy?? do you want me to die???? how he kept saying there’s a good boy???????? ⁄(⁄ ⁄·⁄ω⁄·⁄ ⁄)⁄
4a this group should be called 4some
why is everyone tryna fuck the omega?? is this the whole plot???