there is serial killer ( psychopath ) who kill ML is girlfriend then ML track him so easily but did not kill him because he want him to make more victims just like his girlfriend
ML was full responsible for his girlfriends fathers death just for his enjoyment
then at the end he torture villein family not villein he give him easy chop chop death
so girlfriends family die for his enjoyment and that man even claim to love his girlfriend

ML was just similar with all other Korean ML SELFISH AND SELF CENTERED until the end
he wanted to torture killer for his own self satisfaction and he fail to do that miserably, he end up torturing an innocent child and 2 old parents. but killer enjoy his life and die easily and would rape his girlfriend in afterlife .
it doesn't look that he even loved his dead girlfriend at all, she is just a excuse for him to do all those things because he is also similar to them a Psychopath

ML was busy showing his arrogance in whole story that he is better then them, but you failed to protect your woman so no matter what you do your a loser so stop that show off and kill or torture him for all his life....

kill his son and feed him his own son body parts.

ML is just a IDIOT psychopath who is trying to pretend he is something more then that. and failed at everything he did miserable but he still believe he did something ?
if i could give rating in minus i would have given -10000 to this HYPED shit of a story