Some trivia:
The triplets have been Kyunwoo's gofers since he started sponsoring them and he regularly gives them a tough time under the guise of "men bond like this" or "this is important training for them". Back in middle school he'd often send them to buy stuff that Haneul needs/wants and then take credit for it. They can't do anything about it because he is their sponsor. In retaliation they slander and criticize him whenever they can. Too bad he claps back with harsher private training sessions when he catches them. However, no one can deny that his methods have worked wonders in strengthening them and that is why Kyunwoo keeps them around. He needs all the help he can get to overcome the bad ends.
For those that are wondering, no, this will not turn into a harem. Kyunwoo truly only has eyes for Haneul and thinks her beauty is unmatched. If the manhwa doesn't cut out the romantic/intimate content like the first time he stroked her tail, get ready for a lot of cute stuff in the next chapter or two.