Rei is an average-sized young man. He has dull black eyes, thick brows, and mid-length black hair that he usually pulls up and ties into a man-bun, leaving half of it loose. When he wears his hair down, especially on casual days, his bangs fall unevenly across his forehead and reach past his brows, giving his hair an unkempt appearance. he displays a shut-in attitude, barely speaking or making eye contact. He plays video games on the couch and relies entirely on Kazuki to do basic tasks.