Yoon Bum is a scrawny young man with short cut black hair with parted bangs, black eyes with noticeable bags, and a youthful face. He can be very anxious and shy around people he doesn't know, but he can become aggressive when pushed too far. Bum can become obsessive if he grows attached to someone, especially if he gains romantic feelings for them. Has a hard time discussing family matters since he has a dark past with his own abusive uncle. Has been diagnosed with BPD.