Nobunaga Asakura, the protagonist’s childhood friend, attends the same elite high school but a separate class, blending academic excellence with a magnetic, cheerful demeanor that earns him admiration as a bishōnen. His vibrant passion for anime, manga, and otaku culture eclipses his polished image, securing him the moniker "Kaiser" at Akihabara’s Animate store, where his relentless patronage earned one of three exclusive golden membership cards. A revered fixture in the district, his encyclopedic knowledge of its streets and subcultures is celebrated, immortalized by a framed photo of him shaking hands with the @Home ~Café manager displayed inside the establishment.

Though his charm captivates peers, his unabashed geekiness deters romantic prospects. He maintains a casual, observant stance toward the protagonist’s deepening bond with Haruka, subtly nudging pivotal moments—such as steering the protagonist toward the library where Haruka’s secret surfaces—without overt meddling.

His home life features a younger sister, Mahiro Asakura, who dismisses him as a "hopeless otaku" and ridicules his hobbies, though their dynamic remains unexplored in the anime adaptation. Across official media, Nobunaga’s backstory stays largely undefined, with spin-offs and films preserving his role as a static yet pivotal figure: a reliable, humor-infused ally who sparks plot advancement.

Regular appearances at Comiket and lighthearted exchanges with characters like Nanami Nanashiro cement his integration into the series’ social tapestry, though his persona remains consistent—a steadfast, otaku-hearted catalyst who thrives in the background, steering events without personal evolution.