
I don't how you are still confused.
He was sending the monsters to rape Chiwoo in order to terrify Chiwoo and make Chiwoo feel safe only with him and at the same time he was sending monsters for Sunny magic boy. At first he didn't know Chiwoo was Sunny contractor but, he was already aiming for monsters to attack Chiwoo all along. So, he know that the monster where attacking Chiwoo and he did learn along the way that Chiwoo was Sunny's contractor.
He wants to become Chiwoo safe spot, the only person on Chiwoo's life, the only person Chiwoo's feel safe with. What he feels isn't love, it's obssession. He's willing to break Chiwoo, just to keep him to himself.
Why everyone hate hwan? He wasn't aware of beginning rapes .now he is just tooooo possessive. It's not like it's a huuuuuge flaw I'm sure a little couple therapy will fix things .