Responses

Theory but more like overused cliche. Sunbae is in love with Blondie. Blondie likes Blackie. Sunbae sees their relationship is getting better (or assumes that since Blackie came out of Blondie's house). Sunbae is on a journey to destory anyone close to Blondie.
I actually really wanted Blackie to be with Sunbae n make Sunbae into a better person. Guess that's out the window
Why does sunbae hate him (black haired guy)