Description
Kouhai-chan works as a junior office employee in Sales Division Two at an unnamed trading company, guided by her senior colleague. She possesses long brown hair parted to the right, frequently secured with a left-side hair clip, deep-blue eyes, and a distinctive mole near her right eye. Her figure includes a notably large bust, measured as J70 cup with a 101 cm bust size, which developed from B-cup in elementary school to G-cup by the end of middle school. She typically wears formal business attire: a dark blue jacket, matching skirt, and a white dress shirt.

Personality-wise, she is capable, bright, welcoming, and a quick learner, exhibiting an eagerness for praise often likened to a dog's loyalty. She maintains a strong sense of responsibility and adherence to workplace etiquette, though her figure draws unwanted attention, causing occasional workplace distractions. Inheriting low alcohol tolerance from her mother, she becomes loud and disrobes when intoxicated, requiring supervision from her senior or friends during social events; despite this, she enjoys drinking in moderation. Her interests include cosplay (portraying characters like Mai Shiranui and Tifa Lockhart), otaku activities ("Otakatsu"), sports, and appreciating cats. She dislikes art, struggles with heat as a self-described "northerner" (likely from Hokkaido or Tohoku), and prioritizes sleep over appetite or sexual desire. Romantically, she prefers "gentlemanly" individuals.

She joined the company as a junior employee, improving Division Two's work atmosphere despite attention from rival divisions. Her professional relationship with her senior evolves through collaborative tasks like product presentations and data gathering. A key development occurs when she visits his apartment to interact with his cat, eventually naming it "Fumi-chan" after the sound made when the cat presses against her breasts. These visits become frequent, facilitating deeper personal exchanges, such as discussions about student-teacher relationships where she empathizes with the student's perspective, hinting at similar past experiences.

Across official media, her bond with her senior intensifies. Workplace rumors about their relationship surface after colleagues notice she only drinks alcohol in his presence. Though he privately imagines a future with her, both publicly deny romantic involvement. Key milestones include her nursing him after a hand injury, introducing him to her friend Rikei-chan (a graduate student), and jointly joining a gym to improve his health. Her birthday celebration involves a walk through town, where her senior grants her access to his pet camera as a gift. They later frequent the Tawawa Bath with Rikei-chan during summer.

In the OVA, a notable incident occurs when she forgets to fully zip her skirt before work. After her senior points this out, she jokes about being "spoiled for marriage" and teases him about taking responsibility, subtly indicating her romantic interest. Her protective nature emerges when misunderstandings arise; she firmly corrects Rikei-chan's assumption that her senior exploits her, demonstrating loyalty and rejecting negative insinuations about their relationship.

Her personal history includes using a fictional countryside boyfriend to deter suitors and participating in a college gaming circle. She shares a strong resemblance with her younger brother, who can passably crossdress as her. After moving to a new apartment with cockroach issues, her senior and Rikei-chan assist in resolving the problem.