Tsumugi is a sweet student who speaks in a docile and gentle way, but she becomes very passionate when she talks about her favorite series or cosplays, having a habit of slipping infamous quotes from various sources into the conversation. Being a self-proclaimed introvert, she also tends to ignore people while she's in her thoughts, no matter how many times they try talking to her, and appears rather distant at times. She tends to call herself and everything that she has done "plain."