Tōbaru-sensei teaches classical Japanese literature at the high school attended by Reina Aharen and Shōta Raidō. She possesses long black hair, narrow eyes lending a naturally stern expression, and typically wears professional attire: a charcoal grey sweater over a white dress shirt, glasses, a maroon skirt, and brown shoes. This stern exterior starkly contrasts with her intense emotional reactions, especially when observing the innocent interactions between students Reina Ahiren and Shōta Raidō. Witnessing their relationship often overwhelms her, causing severe physical symptoms like nosebleeds or coughing up blood, sometimes forcing her to pause class or faint. To build tolerance, she conducts nightly mental exercises, imagining various scenarios involving the couple. Her teaching method incorporates archaic Japanese vocabulary; she uses "あはれ" (aware) to describe poignant moments and "をかし" (okashi) for charming observations, often blending these classical terms with modern English phrases like "aware of the year" or "most valuable aware". Professionally, she holds a longstanding tenure and deep expertise in Japanese history and traditional cultural practices, including classical games like Hanetsuki, where she decisively defeated Raidō and his friends. Outside academics, she maintains a close friendship with fellow teacher Miyahira-sensei, who calls her "Momo-chan". They frequently share meals and social outings, during which Tōbaru occasionally expresses concern over Miyahira's eating habits. As the homeroom teacher for Reina and Raidō's second-year class, she exhibits strict classroom management while privately nurturing a fervent investment in their relationship, interpreting their interactions through a lens reminiscent of Heian-period classical romanticism. Her surname means "peach field".