I think that what happened (after watching? seeing? the RAW for the chapter 36) is that the overzealous gang or whatever it is of the white hair guy (I just can't remember names in Korean) confuse the let's say evil brother with the other one and attacked him. But it was not really meant for him. That or the evil brother did something to white hair guy and he was looking for revenge, but it is not clear to me if he knew about the brother before or not.
SPOILER
I think that what happened (after watching? seeing? the RAW for the chapter 36) is that the overzealous gang or whatever it is of the white hair guy (I just can't remember names in Korean) confuse the let's say evil brother with the other one and attacked him. But it was not really meant for him. That or the evil brother did something to white hair guy and he was looking for revenge, but it is not clear to me if he knew about the brother before or not.