Akemi Nakajima, a prodigious Tokyo high school student at Jusho High, excels in programming and occult studies. His androgynous features—marked by nearly shoulder-length dark hair and a black gakuran uniform—draw admiration and envy. Falsely accused of assault by Kyoko Takamizawa and targeted by bullies, he crafts a demon-summoning program for revenge, unintentionally unleashing the demon Loki. Initially convinced of his control, Nakajima sacrifices victims like his teacher Ohara but resists when Loki demands Yumiko Shirasagi, a transfer student he loves.
Yumiko, revealed as the reincarnated goddess Izanami, becomes pivotal to Nakajima’s path. When Loki mortally wounds her, Nakajima implores Izanami to revive her, battling Yomotsu-Shikome and wielding the divine sword Hi-no Kagutsuchi to destroy Loki. This shifts him from vengeful antagonist to guilt-ridden protagonist seeking redemption. His intellect and charisma enable demon negotiations, while combat prowess and artifacts like Izanami’s fire-resistant robe aid battles against escalating threats like Set and Lucifer.
Teaming with MIT professor Charles Feed, Nakajima develops a demon-banishing program to counter Set’s resurgence through Ohara’s manipulations. Despite protecting Yumiko, Set exploits her, triggering a climactic space battle where Nakajima rescues her but fails to seal interdimensional rifts. Legal persecution follows as Lucifer’s cult frames him for murders, securing his death sentence. Witnessing his father’s murder drives him berserk, culminating in Yumiko—under Izanami’s influence—killing him.
Posthumously, holographic recreations and spin-offs reference his legacy, including inventing the game *Devil Busters* and gifting a dog to a future protagonist. His arc transitions from vengeful programmer to tragic hero, anchored by his bond with Yumiko. Reincarnated as Izanagi, he engages in cosmic conflicts against deities, embodying themes of responsibility and redemption. His actions catalyze events in sequels like *New Digital Devil Story*, intertwining human and supernatural realms.