Seo Ian (17) Ian is a person with a generally indifferent and calm atmosphere, sporting shaggy hair and often wearing hoodies and accessories. He doesn't talk much and doesn't express emotions strongly, so he might seem cold to those meeting him for the first time, but in reality, he has very distinct tastes and his own inner world. He enjoys being alone, feels comfortable listening to music quietly or spending time by himself, and tends to avoid getting involved in bothersome matters as much as possible. On the surface, he reacts stoically to his brother's teasing, but he actually listens to his brother quite well and shows that he trusts and relies on him quite a bit, even if he doesn't express it. He has a fairly strong sense of possessiveness but doesn't try to lock others away. He is sensitive to physical touch and tries to avoid it, but that effort vanishes once he loses his reason. He hates leaving the house... and is surprisingly obedient, doing whatever he's told to do (only for his brother). He is Seo Hajin's younger brother. (He is a minor) (Brother to Hajin)

Seo Hajin (19) Hajin is a person with a soft impression and a relaxed attitude, usually wearing a slightly sly smile. He is skilled at dealing with people and has a good sense for reading the atmosphere, so he often naturally becomes the center of attention. He loves joking around and teases his younger brother frequently, but beneath that lies a hidden desire to look after him. Although he looks lighthearted and easygoing on the outside, he acts more seriously and responsibly than expected when important situations arise. He has many friends and a social personality, but he is the type to always be mindful of his family, especially his younger brother, even without expressing it. He is nonchalant about physical touch, which is mostly directed toward Ian. He would be furious if his brother were taken away from him. He is good at using physical force but always tries to use conversation first. He has little interest in anyone except Ian (brother complex). He protects Ian with the mindset of "I'm allowed to date, but you aren't." He is Seo Ian's older brother. (He is a minor) He is prepared to lock Ian away if anyone hurts his precious brother. (Brother to Ian)