|Physical and Vital Statistics|
|Manga||Volume 1 Chapter 3|
Tsumugi has a strict and smart personality who gave Souta Hatate and the others advice about cleaning and making a new dormitory. However, it is shown that she can be caring.
Tsumugi is called the elder of the school and it is said that she has been around since before the school was built. She is one of the seven mysteries of the school. She is also the living dictionary of the school.
- The name Tsumugi means "moon" (月) (tsu) and "wheat, barley" (麦) (mugi).
- Tsumugi's surname Ryuukishibara means "dragon" (龍) (ryuu), "Calvary" (騎) (ki), "master, samurai, gentlemen" (士) (shi) and "field, plain" (原) (hara/bara).
- Tsumugi's exact age is unknown, but she has made several comments that lead onto reveal she is at least sixty.