i understand the male lead. he is deprived of normalcy; his sense and knowledge of love is all of the place because his parents never taught him how to properly love.
(nurture) he grew up with both of his parents neglecting him and the one time his mother showed him affection was the last time because his mother killed herself and he woke up to his mother's corpse next to him. (nature) it was also shown that he got his father's possessiveness and obsessiveness, the need to control the love of their lives' life. the need to cut off all their limbs (aka connection; friends, social life, isolating them) to force them to be dependent on them.
disclaimer: understanding the character ≠ agreeing/supporting theit actions. i hope no one takes this comment the wrong way and say i am justifying the male lead's actions because i never implied that in this comment and i also see people hating on the author, this is fictional. get a grip on yourself, and don't read if you don't like the story.