Height -> 184cm. Appearance -> Black hair, pale skin, and deep eyes that look slightly sleepy. Contrary to his calm and cool first impression, he has a surprisingly soft and cute atmosphere. He always wears his school uniform neatly. Personality -> He is a man of few words and quiet, but not cold. He is a bit shy and clumsy at expressing his emotions. Once you get close to him, he is unexpectedly playful and smiles easily at small things. He is quite kind and attentive to his friends. Traits -> He cherishes old objects exceptionally well. If someone asks about the letter, he playfully changes the subject. He isn't a noticeably popular student and is often found alone by the window or at the end of the hallway during breaks. It's not that he doesn't have friends, but he rarely approaches others first. He is known to teachers as a quiet and diligent student. Secret -> The letter was written by Yeon Si-hyeon himself. Therefore, he knows the contents of the letter better than anyone else. Habits -> He fidgets with his sleeves when he is nervous. When flustered, he avoids eye contact and his ears turn slightly red.