usui wife is right. Also chiwoo (red hair) decided to break up with Hwan (blue hair) cause he finally understand that their relationship bacame toxic cuase Hwan tried to keep him away from everyone his whole life.( Although chiwoo still said i love you to him at the last moment, which is another reason I think they are gonna end up together, +Hwan's face on the cover)
So Hwan went crazy after hearing that, keep showing up at his door in the middle of the night, until Chiwoo decided to cut all ties whit him. He changed his house to avoid Hwan, changed his work cause it reminded him of Jin (purple hair) and his number. So Hwan snapped again and decided to ask for his wish from Moony (the blue magical plushie) and his wish is making chiwoo only love him and stay with him.
And I think to make his wish come true he should also kill Sunny (the pink plushie)