That guy wasn't obsessed with Sehan's safety. He wanted to get rid of Chaon because him and his dad witnessed something they weren't supposed to, I think. Can't remember in which chapter they show it. But he couldn't flat out get rid of Chaon because Sehan made a deal with his dad, the boss, that he would take over if they didn't kill Chaon. I think. I might be wrong. I need to reread the story. But I'm also upset he gets away with all of it.

I'm ecstatic for the happy ending and I love seeing Sehan and Chaon happy and away from the adults that failed them BUT one thing I didn't like was how that scar faced motherfucker who has some serious obsession with Sehan’s safety and the same guy who used to lock Chaon in a dark place as a child got away with little to no consequences other than that one time Sehan really gave him a beating. I want him tortured slowly till he dies or like have him rot in the same suffering Sehan and Chaon both went thru. Because of that same guy my man Chanseung lost his arm AAAAA I want him and that cheongseong director to suffer 100x more.
Also, I am no psycho but I tell yall when I saw Sehan blew that white haired mf straight in the head I was filled with overwhelming ecstasy
There were alot of stuffs that weren't fleshed out in my opinion but overall I love the story, I love the characters. It was rushed but given the creator's health it's very understandable how this manhwa was cut short. This is prolly not gonna happen but I yearn for side stories T^T