Tsumugi is friendly and always willing to help others, which often leads to Natsume ordering him around. Eichi even points out that it's easy to take advantage of this disposition. His understanding of friendship is quite flexible. He describes his friendship with Natsume and Kuro's with Shu as a "good coexistence" relationship despite their mutual disagreements, frequent arguments, and/or physical altercations. Although he doesn't always read situations well in his own interactions, frequently displaying a lack of empathy and tact, Tsumugi demonstrates remarkable social awareness in several stories, commonly being seen giving advice to those who come to him for it. At other times, he is praised for his level-headedness, even in the face of unexpected consequences. He is also well-versed in the topic of mental health, including the symptoms of others, though in some cases he prioritizes his own view of others' symptoms over theirs. He frequently teases other characters, though it's not necessarily in a friendly way. He has low self-esteem, often speaks of himself with destructive criticism but says it as if it were normal, he is excessively honest, often saying inappropriate things without intending to hurt but it's what he thinks, he is quite anxious, but compensates for it by being overworked, accepting jobs that aren't his just to do a favor, being overly helpful and socially awkward, getting nervous around women
