hmm. I don't if you've read the series yet but if you haven't then there is have some BL action in it.... probably much more later in the series...
As for romance.... Both their love is pretty unhealthy. Just take the name very literal.
I would say...possibly... a case of stockholm syndrome or maybe Lima syndrome.... ?
Yes and no. There is romantic themes more on the very twisted side. Bum was in love with him enough to stalk him while Sangwoo (I'm not too sure about him) is slowly showing affection towards his victim. Since this is tagged as a BL you'll more than likely see more romance later on. It's a relationship forming a very unhealthy one but it is forming.
can somebody tell me why is this tagged as romance and yaoi? is that the intention of the artist?