Naka ga Warusugiru Osananajimi ga, Ore ga 5-nen Ijou Hamatteiru FPS Game no Friend datta Ken ni Tsuite.

Shintarou Amekawa and his next-door neighbor, Natsuki Haruna, share a strained relationship as childhood friends who can barely stand one another. Though they were once inseparable in their youth—even making a childhood promise to marry—Shintarou's deep obsession with a competitive first-person shooter (FPS) game gradually drove a wedge between them. Over the years, their bond eroded into mutual hostility, marked by harsh words and cold exchanges every time their paths cross. The dynamic shifts dramatically when Shintarou is tasked with delivering school handouts to Natsuki after she leaves class early. For the first time in five years, he steps into her bedroom, only to find it unoccupied and dominated by a high-end gaming setup. Glowing on the monitor is the post-match screen of the very FPS game he has dedicated years of his life to mastering. Staring at the impressive statistics, Shintarou is stunned to recognize the username and exceptional kill count belonging to the world's second-ranked player: the legendary sniper known as [2N]. The realization hits him with staggering disbelief that his abrasive, estranged childhood friend is none other than his elite in-game comrade and closest virtual ally.