Tsumugi Isuzu is a minor character in the 'Toaru Majutsu no Index' series. Although her appearances are brief, she plays a supportive role within the storyline, often seen assisting other characters. Her personality is gentle and she is known for her calm demeanor. Tsumugi has a background in science, which occasionally aids the protagonists in their encounters with various supernatural phenomena. Her scientific knowledge provides valuable insights, contributing to the resolution of conflicts and the progression of the narrative.