Naofumi Tokino is a combat pilot stationed at Urisu Base (Area 262) under the Rostock Corporation. He shares quarters with fellow pilot Yuichi Kannami, forging an instant bond by guiding Kannami through base life and introducing him to off-base social spots. Tokino frequents Daniel's Diner and a neighboring brothel, gaining a reputation as a habitual womanizer who regularly consumes alcohol from the base's beer refrigerator. This hedonistic lifestyle reflects his self-identification as a perpetual adolescent, a trait inherent to the genetically engineered Kildren inhabiting this world.

Despite his recreational pursuits, Tokino exhibits exceptional combat skill in aerial engagements. He employs daring, unconventional flight maneuvers that frequently catch opponents off-guard, securing him victories in dogfights. His combat philosophy prioritizes individual survival over teamwork; he often breaks formation after battles, sometimes returning to base alone while leaving wingmen to their own devices.

Tokino maintains distinct relationships with colleagues. While generally detached from most fellow pilots, he develops a protective concern for Kannami, particularly regarding Kannami's interactions with their commanding officer, Suito Kusanagi. This concern surfaces through observational warnings and advice, hinting at a layer of responsibility beneath his carefree facade. His character shows subtle development through his growing investment in Kannami's wellbeing, contrasting his initial purely pleasure-driven portrayal.

His philosophical outlook emerges in discussions about existence's cyclical nature, where he justifies his lifestyle by asserting his right to "childish" behavior as someone eternally adolescent. This perspective reflects the Kildren's psychological adaptation to their repetitive lives and inevitable fates.