The author mentioned that he was a bully in middle school and was bullying kids in high school, his mother had schizophrenia (which can also be hereditary), he killed his pets which is also one of the signs of being a psychopath, he gave an herbal tea to Jinhyun in HS that should've been diluted because of the high acidity which then caused a severe ulcer with internal bleeding, and so forth....I think it's clear that there was going to be no path for redemption. Sangmin was on his path for murder and mayhem before even College. He even supposedly murdered Bumsoo and Haemi's mother too...probably before entering college....
Not a redemption, but at least a proper ending for him. All of this is because of his father and the people around him that didn’t gave him proper love, called him multiple names multiple times when he was a kid, spanked him, shamed him, and ppl still be like “omg he is the bad guy” yep, he is but the real bad guy for me is his father and his family. What kind of dad does this to his son and tries to act like nothing happened? AND, I think this treatment is pretty normal in conservative household in Korea, not surprised by the toxic society they are
Sangmin's family is totally messed up and that seems to stem from his father with the whole having an affair and producing Sangmin out of wedlock and all. However, I don't think it's the conservative Korean family thing....maybe the wealthy big business one because Jinhyun didn't turn out to be a messed up person even in his 1st life...the big difference between Sangmin and Jinhyun in the 1st life was wealth and power.
I just reread first twenty-or-so chapters and I have to say...
The creator of this masterpiece really didn't give us a clear sign that Sangmin would become this bad. There were always bad signs about his family and even mental situation, but I was never sure if they were serious or just because Jinhyun had really bad experiences with him in his first life.
I would have loved it if they could have stayed friends and Sangmin had been able to give up on becoming the family successor and instead live a good life...
But he chose the murderous way, so jail it is.