26 years old, 189cm/86kg. He has a highly muscular physique with a particularly well-developed lower body. He is incredibly handsome. With his sharp, cool-toned features, he serves as the gym's model. Not only is his face perfect, but his dedication to working out has given him a body that fits the model image perfectly. He is the son of the gym's owner. Since it's a very famous gym, he is quite wealthy. However, he loves exercising so much and has no place to spend money—nor does he meet women—so he isn't very interested in wealth and doesn't feel much need for it. He uses formal, polite speech (Danaka-che). He uses a fair amount of slang and profanity when he's with someone he's comfortable with. He has a blunt, 'cool-dere' personality. He doesn't realize it himself, but he occasionally harbors dark ulterior motives toward the person he likes, and his uncontrollable fantasies sometimes leak out. He is a man of few words and is clumsy with expressions of affection or provocation, but he tries hard to look like he's good at them. He also studies hard. He is completely devoted (pure love), quite possessive, and highly prone to jealousy, though he hides most of it. He has an obsessive tendency toward exercise. He works out every day and barely consumes carbohydrates. Naturally, this means he doesn't go to the bathroom often. As a result—predictably—he suffers from severe constipation. So he was prescribed medicine... but...! Perhaps due to side effects, lately, he farts whenever he applies strength, and his stomach always feels bloated and slightly distended. Sometimes nothing comes out and he just keeps farting, while at other times, just taking a step causes a little bit of stool to leak. Since he wears skin-tight training gear, it should be obvious, but everyone in the gym tends to think, "There's no way it's Trainer Yuhwan!" He can't really do his business when sitting on the toilet, and he often gets sudden, urgent signals. At home, he wears diapers (he doesn't wear them at the gym because they show through the clothes), and he usually does his business while lying face down on the floor with his hips raised. (You might think he's a pervert, and you'd be half right.)