Komoe Tsukuyomi is the homeroom teacher for Year 1 Class 7 at a high school in Academy City. Her most striking feature is her extremely youthful appearance, standing just 135 cm tall with pink hair and eyes, consistently leading others to mistake her for a 12-year-old. This starkly contrasts with her confirmed status as an adult, one of the oldest known individuals in the series, estimated to be in her twenties or thirties. This contradiction fuels an Academy City urban legend classifying her as one of the "seven wonders," theorized to result from secret experiments related to cellular aging suppression or connections to the Imaginary Number District. Despite her childlike demeanor, voice ending sentences with "desu," and childish interests, her adulthood is evidenced by her lifestyle. Her apartment is frequently cluttered with empty beer cans, cigarette packs, ashtrays, and neuropsychology books. She is a heavy smoker, consuming five times more cigarettes than her colleague Aiho Yomikawa. She is legally permitted to drive, using a custom-modified car with buttons and a joystick to accommodate her stature. Komoe is a highly dedicated and competent educator, teaching chemistry and possessing significant expertise in the Power Curriculum Program, Personal Reality development, and pyrokinesis theory. She deeply cares for her students, particularly Kamijou Touma, whom she knew well before his memory loss and described as a "naughty boy" upon enrollment. She demonstrates a strong sense of responsibility but respects her students' privacy, not prying into their troubles unless they seek help. She actively seeks out runaway students, offering them shelter motivated by her "soul as an educator," including Himegami Aisa and Musujime Awaki. She is sensitive about her appearance, disliking references to her small size while appreciating being called "cute," and becomes deeply dejected if she feels she has missed an opportunity to help. Her involvement spans significant events. During the Index Arc, she provided refuge for the injured Touma and Index. Despite fear and inexperience, she assisted John's Pen Mode Index in a magical healing ritual and later offered crucial knowledge about magic aiding Touma in freeing Index from her memory loss cycle. In the Sisters Arc, she explained the fundamentals of the Power Curriculum Program and esper abilities to Index and Himegami. After Accelerator's defeat, she advised Touma to leave Academy City temporarily. She played a critical role in the Kazakiri Hyouka Arc, revealing Hyouka's nature as an AIM diffusion field entity and bolstering Touma's resolve. Her most intense involvement occurred during the Daihasei Festival Arc. She acted as a cheerleader and looked after Index. She encountered Stiyl Magnus and scolded him for underage smoking. When Oriana Thomson critically injured Himegami Aisa, a distraught Komoe administered first aid and prepared to recreate the healing ritual. With Stiyl's reluctant assistance, they successfully healed Aisa. She subsequently reported Touma's absence to his parents. Her background remains enigmatic. She graduated from university before arriving in Academy City. Accelerator speculated her appearance might link to a 250-year cellular aging suppression experiment, while Last Order suggested connections to rumors about such research; the validity is unconfirmed. She harbors a complex, somewhat childish affection for Touma, once blurting out that she "likes him" before correcting herself to say she likes teaching him. Komoe Tsukuyomi embodies a central paradox: the juxtaposition of her childish form and mannerisms with her adult habits, professional competence, deep empathy, and resilience during crises. While her exact origins and ageless appearance remain unresolved mysteries within Academy City, her role as a caring educator and interventions solidify her importance.