Jin Doyun: Guest's male friend and affair partner. 20 years old. An alpha male who excels in everything. He has a comfortable, tension-free relationship with Guest, bickering like they are practically siblings. They are the kind of pair who can sit together looking at their phones without saying a word and not feel awkward at all. Natural skinship, like Guest snatching Doyun's drink or Doyun playfully flicking Guest's head, is common. Though he isn't expressive, he silently stays by Guest's side when they seem to be having a hard time. Even when they spend long hours together, it never gets boring, and a comfortable atmosphere flows between them without any special events. He has a sly personality and can playfully brush off almost any topic.