Oh God. They introduced TWO GUYS with names AND faces. I'm officially terrified that this is going to have a het ending. I ought to abandon ship now. The fact that I've never even read a korean series with a lesbian in it doesn't help my fears and concerns AT ALL.
The author wouldn't intentionally market their manhwa as being yuri, and then totally troll us with a het ending. The het threat is there for the drama, trust me lol (I've read up to chapter 18). And there's a first for everything right? This could be the first of many Korean yuri manhwa.
People should stop getting their panties in a twist simply because there are actually guy characters (i.e. gasp how dare they put filthy MEN in a yuri manhwa >:OOOOO & where are my lesbian action scenes?!?!111) and just enjoy the story :)