Sora Kojima serves in the 108th Guard Squad, a unit stationed in Aomori and dubbed a "reject camp" for pilots who failed qualification for elite Hokkaido forces. This squad operates with scarce resources and low standing yet contends with constant enemy threats.

Personality-wise, Sora embodies the ISTJ traits: practicality, reliability, and strict adherence to protocols. His Enneagram type, 6w7, reflects a core drive for loyalty and security-seeking, tempered by a secondary wing of enthusiasm and spontaneity. A recurring personal refrain captures his perspective: "I know it's hard to believe, but even I have my limits."