Although he can be high-strung at times, he is usually gentle in his demeanor. He is interested in fortune telling and divination, and keeps a lucky item of the day as part of his daily routine. He serves as the library chairman and often receives harsh treatment by Natsume. A member of the unit Switch.
Tsumugi is a tall young man with an average build and a paler complexion. He has dark blue, wavy, tousled hair with long bangs that cover his forehead and the tips of his hair curved. It is of shoulder length with turquoise streaks on the left side. He has gold eyes. He also wears large, black rimmed glasses. He wears the school uniform with his white shirt unbuttoned at the collar a bit, the blazer buttoned up neatly and a dark grey sweater underneath it; together with a green tie that's slightly loosely tied and tucked under the sweater.