Mitsuko Torii is a teacher and the school physician at the Constant Magical Academy, where she also works as a magical researcher. She serves as the homeroom instructor for class 1-A, which includes the protagonist Akuto Sai, as well as Keena Soga and Junko Hattori. She has long blonde hair and is usually seen wearing glasses and a lab coat. Her personality is marked by a mischievous and openly scientific curiosity, most notably displayed in her repeated half-joking statements to Akuto that if he were to die, she would turn him into an undead creature to study the composition of a Demon King. This fascination with his potential as a subject for research drives much of her interaction with him, though her attitude remains playful rather than menacing. As a faculty member, she fulfills the roles of both instructor and medical caretaker, occasionally providing treatment or advice to students. Beyond her fixation on Akuto, little is shown about her deeper motivations or personal development within the story. Her notable abilities are rooted in magical research and medical knowledge, rather than direct combat or supernatural powers. She functions primarily as a supporting character, adding a layer of eccentric humor and scientific detachment to the academy setting.