Hiroshi Nakagawa, older brother to Ouran Nakagawa, lives as a reclusive NEET. Once a popular and handsome high school student, he gained significant weight after university graduation, obscuring his neck and jawline. He avoids the family business, Nakagawa Motors, spending most of his time indoors.

His social existence unfolds primarily online through a monetized summary blog. Here, Hiroshi navigates two distinct modes: he aggressively targets individuals he deems "high-minded," sometimes resorting to harassment with disturbing images, while simultaneously offering kindness and understanding to lonely or struggling youths. This reflects his dual personality, appearing harsh in some interactions yet supportive in others.

His background includes a broken childhood marriage promise to Kadode Koyama; she explicitly declared she couldn't marry someone who looked like him now due to his physical transformation. Hiroshi's storyline diverges between the original manga and film adaptations, creating variations in his narrative outcomes across official media.