Izuna Endo is Shizuna Endo's younger twin brother and her co-pilot for the non-combat Machina Deceive, a unit specialized in electronic warfare. He mirrors his sister physically with chocolate brown hair, brown eyes, and notably feminine facial features. At 14 years old, he sports a bob cut with fluffy bangs and wears the standard JUDA uniform: a black suit, blue shirt, and black tie. Though born in Tokushima, Izuna speaks accentless standard Japanese, unlike Shizuna's Kansai dialect, reflecting their disparate upbringing across Japan. His personality is reserved, serious, and shy, contrasting sharply with Shizuna's brash directness. Programming is his core skill, vital to operating Deceive's electronic warfare systems. He focuses on deploying disruptive tech like the Nerve-crack, which induces psychological distress in targets, making his expertise crucial to JUDA. Deceive demands both twins to function, with Izuna managing its electronic suite.

A narrative divergence exists between continuities: in the manga, Deceive gains self-awareness, traps Izuna in its cockpit during a rampage, and kills him, underscoring Machina risks and pilot-machine bonds. The anime omits this fatality, keeping Izuna active. Despite official records listing him at 157 cm, he stands slightly shorter than Shizuna. His reserved nature extends to hobbies approached with meticulous seriousness, potentially to shield personal interests. Initially, their near-identical looks cause confusion until Shizuna adopts a white hair clip for distinction. Within JUDA, Izuna assists his sister in foundational training for new members. Their partnership—his quiet restraint against her outgoing energy—fuels both Deceive's operations and their daily organizational dynamic.