Let me explain it to you. The red-haired man at the end of the chapter is actually the one who wants Hae-yul. In the early chapters, we saw Seo-in call this man and ask him to come pick up Hae-yul. So who is he? He is Seo-in’s step-cousin, and he was also considered one of Han Jae-won’s closest friends.
After the conflict between Young-won and Seo-in over kissing Jae-won—when Young-won realized that Seo-in had approached him with ulterior motives—Seo-in was supposed to go abroad for the holidays. However, Young-won never went to say goodbye. This was because Jae-won, and most likely his step-cousin as well, were involved in beating Young-won.
After Seo-in’s mother finds out about this, she tries to settle the matter by offering money to Young-won’s father. But in one chapter, we see Young-won, with his arm broken, go to Seo-in’s mother himself and ask for Seo-in’s phone number so he can say goodbye. Seo-in’s mother refuses, saying that she feels too ashamed and that Seo-in must not find out anything. At that moment, Young-won promises that no one will ever learn the truth about how Jae-won abused him.
