Although rude to people he dislikes and that he is goth, Seojun is very caring, protective, and kind to his friends and family. He tends to have difficulty expressing his emotions, especially during difficult times. He acts tough in front of others, but is shown to be sensitive and easily flustered. Coming from a poor family, Seojun's biggest insecurity is his financial stability. He has black hair with bangs that sweep across his forehead towards the right side. He has mono eyelids.