Born nameless, without family, birth certificate, or any identity, the Ultimate Imposter (formerly Super High School-Level Imposter) existed invisibly, devoid of existential meaning. This void drove a life of stealing identities solely to achieve acknowledgment and a semblance of normal existence, not for material gain or power. The constant deception fostered deep-seated mutual distrust, described as a living hell, as the Imposter never intrinsically desired to lie. Food, especially consistent-tasting fast food, provided rare comfort, symbolizing stability. This affinity led to deliberate weight gain to cultivate a distinctive physique. Initially, the Imposter impersonated Byakuya Togami, the Ultimate Affluent Progeny, admiring his underdog story. Later, they assumed the identity of Ryota Mitarai, the Ultimate Animator, to support his work. This involved living together in Hope's Peak Academy's dorms, delivering food to Ryota, and mimicking his reclusive behavior. Despite skipping classes initially, homeroom teacher Chisa Yukizome persistently encouraged attendance to foster camaraderie with Class 77-B. Concern intensified when Ryota collapsed from overwork and malnutrition, prompting the Imposter to seek help from Mikan Tsumiki, the Ultimate Nurse. Trusting Mikan with their secret, they formed a bond and collaborated to monitor Ryota's health. During their second year, Ryota vanished, later revealed as kidnapped by Junko Enoshima. The increasingly distressed Imposter confided in Mikan and mobilized classmates to search. When Nagito Komaeda mentioned spotting Mikan near the school's West District, the Imposter reacted uncharacteristically aggressively. Inspired by Chiaki Nanami's leadership during a crisis, the Imposter tore off Ryota's disguise, revealing their true face—long black hair, green eyes, and a substantial build—to the class, who accepted them without hesitation. This unity led into a trap orchestrated by Junko. The Imposter and Class 77-B witnessed Chiaki's brutal execution, incorporating Ryota's brainwashing techniques into the footage. Forced to watch helplessly, the experience plunged them into despair, turning them into Ultimate Despair. As Remnants of Despair, the Imposter notably impersonated Byakuya Togami again to combat Future Foundation members, using night-vision goggles. After Junko's death, they perpetuated The Tragedy until captured by the Future Foundation. Makoto Naegi, recognizing their brainwashed state, secretly placed them in the Neo World Program to reset memories to pre-despair states. In Hope Arc, Hajime Hinata restored the Imposter and classmates to their original personalities. They intervened to stop Ryota Mitarai's global brainwashing broadcast, with the Imposter participating in persuading Ryota. Accepting responsibility for their actions as Remnants of Despair, the Imposter and classmates voluntarily exiled themselves to Jabberwock Island to atone. Throughout their journey, the Imposter exhibited a polite, meek, and serious demeanor when undisguised, contrasting with performed arrogance like Byakuya's. Despite the burden of deception, they demonstrated genuine kindness, particularly in caring for Ryota and trusting Mikan. The character's arc reflects a quest for identity, culminating in peer acceptance and a commitment to redemption.