Yamaarashi Hotta, nicknamed “Porcupine” for his short, spiky chestnut-burr hair and brash demeanor, is the head mathematics teacher at a Matsuyama middle school where the protagonist works. A native of Aizu, a region steeped in samurai heritage, he cuts an imposing figure with a muscular build and a resonant voice that dominates any room.

Though abrasive at first glance, Hotta fiercely upholds justice and moral integrity, clashing with colleagues entangled in unethical plots. His initial wariness toward the protagonist shifts into an alliance rooted in shared principles, contrasting his blunt honesty against the manipulative schemes of Red Shirt, the vice principal he deems a symbol of elitist corruption.

A seasoned educator, Hotta’s experience grants him authority among staff, while his forthright nature stirs both admiration and tension. Beneath his gruff exterior lies unexpected kindness: he aids the protagonist in finding lodging and dispenses pragmatic guidance. His rigid ethical code drives him to confront Red Shirt directly, exposing the latter’s hypocrisy through bold, decisive action.

Hotta personifies the conflict between traditional Japanese values and superficial Westernization, mirroring critiques of Meiji-era societal change. His unyielding principles and physical vigor counterbalance Red Shirt’s duplicity, highlighting the narrative’s tension between integrity and opportunism. Adaptations preserve his role as a steadfast emblem of ethical guardianship in a morally murky world.