Responses
I think that the dark haired brother doesn't know about the sexual abuse and that he was adopted too. The other brother was keeping a lot of secrets from him. It's clear that the other brother cares for the black haired one a lot. In what capacity, im not sure. So maybe Minjae's revenge is more about tearing them apart.
I don't get it. I thought exposing sa was the revenge? I also get why you wouldn't bc you wouldn't want people to know that you got sa. But what was the leverage here ?