Top mother left him and his dad because she worked for bottom dad and he was gonna make their life hell if he didn’t have her or something so she went to him. So top mother is married to bottom dad which makes them step siblings now. Idk if they are still married or if the bastard killed her off but I don’t think they are still step siblings anymore.
I think we lost here.the white haired guy and the grand father is two diff. People ..your explanation is so messy..cho the white haired guy is whom the seme's mother remarried to.while yeshin the bottom's grandfather is the chairman Lee..and mother of the seme and the whitehaired guy doesn't have children ..how did you end up saying they are related...are you talking about the bottom's brother who hanged himself?..thats is the ome who have mistress that turned out its yeshin's mother..
My explanation wasn’t messy. I thought the dude was yeshins dad not his grandad. If he was yeshins dad, that makes them stepbrothers. Since it’s the grandpa, that makes it step uncle and step nephew.
Yeshins HALF brother shares a father. I didn’t mention him since he’s irrelevant to this. Also, I got confused because I saw someone else call him step father so I thought I was mistaking the white haired dude for a grandpa instead of a father. That’s on me for flip flopping without verifying who he actually was.

That makes him yeshin’s uncle????????????