Izumi Makihara is a supporting character in the anime, primarily known for being the childhood friend and classmate of the protagonist, Sanpeita Kobayashi. She is a teenage girl with brown hair cut to neck length and blue eyes, and her appearance is noted for including elements like a school uniform, stockings, a tie, and distinctive cheek curls.

Her role in the story is largely defined by her romantic feelings for Sanpeita, which she harbors secretly but actively tries to express. As his childhood friend, she occupies a position close to him, but her advances are often unsuccessful, as Sanpeita appears to be mostly oblivious to her affections. This dynamic creates a significant source of motivation for her actions throughout the series.

Her position becomes more complicated with the arrival of the small, aggressive mecha named Kemeko, who claims to be Sanpeita's wife. While Izumi desires to get closer to Sanpeita, she must contend with this bizarre and violent rival for his attention, as well as the mysterious girl named M.M. who controls the mecha. This situation places Izumi in a romantic subplot that contrasts her more traditional feelings with the chaotic and science-fiction elements introduced by Kemeko. Her unrequited love and the persistent obstacles to her goal form the core of her character's journey. While the main series does not feature dramatic transformations in her status, a dedicated short OVA special focuses specifically on her, highlighting her significance to the narrative. She does not possess any notable combat abilities or special powers, with her character grounded in the everyday social and emotional drama of the high school setting.