
The dad is a pro lifer for real. He doesn’t harm the baby because “all children are born innocent”, but had no issue orphaning him in infancy and deliberately creating an environment designed to destroy him from birth, including getting him hooked on drugs. Sangjin is a pos, but it’s actually kind of devastating to learn that he never had a chance of being normal or getting an exposure to decent role models.

So true. The father just hated the mother so much that he ruined the son. He used him and couldn't care less about him. They, the ceo and the secretary (father and thennthe son), just wanted sangjin to die as a drug addict or something. Like you said, he never had role model, nobody protected or defended him from all this.
Hope the bottom never discovers the truth because it's awful. What a shitty father and mother. Even the secretary. The woman was a serial cheater and a golddigger, he could have had a divorce or give her money. But no, he wanted to mantain the image of a chaebol couple so much he ruined everything and everyone. He became a killer, an abuser, a cunning man... He just wanted revenge because of the cheating, mess with the other son he hated and called it an "example". Glad the father died. He didn't loved biological his son at all.
The secretary was following orders but still... ugh. Only terrible terrible were around the bottom. He really struck luck with the firefighter.