Firstly I think the creator has confirmed that the next chapters may be free on angst so let's relax. I'm seeing a theory that taegu may become the villian but I think it's haeyool. Regardless of his weird ass feelings taegu has some respect for yw that he would actually let it go. I think he was the one at the door and heard yw moaning and realized he and yw will never be and he left the bag. The one we should be worried about is haeyool. He is obsessed with yw and would use the redhead cousin to hurt yw for being with seoin and basically rejecting him. He seems unhinged considering how he was blackmailing yw.
I really hope we are given some fluff until further notice. I think the season will end with chapter one being revisited.