To kill or to be killed seems to be the biggest divide between the two brothers. I theorized that the present times reflects the true events of the past and Seungmin’s involvement point to there being a third party he’s only acts a stand in for them. At some point, I questioned whether Hanseob may have actually played a hidden but bigger part in both of their povs.
https://www.mangago.me/home/mangatopic/23296969/

This sounds like another tall tale if the curse was as common as the father insists what is the reason for having his sons replicate the eldest's handwriting? It's not as if he's trying to pass them off as the first born son at some instances it would seem as if the death of the first heir is being covered up. Whatever the case is he left behind some big shoes to fill. In writing, studies and looks Dohun meets a lot of the criteria required to replace the late heir.
I keep finding myself rereading the part their father says, “If I slip up and accidentally kill him in the process will you come after my throat? Just like Hanseob did?” Followed by Dohun ensuring his father he wouldn’t kill him bc if Yuwon were to die, he’ll die too. Yuwon’s car accident suddenly came to mind we don’t know who hit him or his condition afterwards. With the way Dohun answered I questioned whether he’d actually do anything had he been at the scene but he says he’d only act had Yuwon died. To me, this translated that he’s no hero he’s always been a bystanding cuck. (He didn’t even kill all the bullies for Yuwon and we see him befriending all his enemies in the present)
I thought the scene paralleled with the scene where Hanseob’s ear was cut off they’re both being threatened with the position of the company’s next heir. In this chapter it’s revealed that there was someone being used as leverage over Hanseob. The dialogue never broke when the topic switches between brothers almost as if implying they were being cornered by the same thing. While we don’t know what Hanseob’s exact motives are we can see both of them want the father gone. Between the brothers he’s easier one to coerce into doing their father’s bidding since he actually falters at his threats but out of the two Hanseob is the one I can see actually going through with actually carrying it out. What is the leverage their father has on Hanseob? Also, between the two brothers why does he only graze Dohun’s ear but cut off Hanseob’s? I thought maybe this gruesome physical alteration was another requirement that needed to be done before replacing the first successor.