Saito is the tactical sniper and firearms specialist of Public Security Section 9, distinguished by his limited cyberization. Only his left eye and arm are prosthetic—the eye linked to satellites for precision targeting. These replacements trace to a mercenary clash in World War IV Mexico, where he fought for Red Bianco against UN peacekeepers commanded by Motoko Kusanagi. During their encounter, Kusanagi’s strategic deception provoked a sniper duel: glass shards from his shattered rifle scope destroyed his left eye, and her blade severed his arm. This confrontation precipitated his recruitment into Section 9, though ambiguities linger around his retelling of events, subtly referenced in a poker game story from *Stand Alone Complex: 2nd Gig*.

After WWIV, Saito’s allegiance to Kusanagi became unwavering, her directive to join Section 9 marking his first accepted order. In *Solid State Society*, during an African operation, his prosthetic arm sustained sniper fire while eliminating a target. A later exchange with Batou alluded to possible cardio-pulmonary cybernetic upgrades, their full scope undefined.

When Section 9 disbanded post-Simultaneous Global Default in *SAC_2045*, Saito enlisted with the mercenary group GHOST in the United States. There, he engaged in countering post-human threats and economic warfare by global powers, deploying his sniping skills and tactical acumen against enhanced adversaries. He later reunited with Section 9 under Aramaki’s leadership, aiding operations against post-human conspiracies and cyber conflicts.

Despite minimal augmentation, implied enhancements to his legs or back enabled Saito to match his heavily cyberized teammates in high-stakes operations. His mercenary history shaped a pragmatic, efficiency-driven approach to missions, often sidelining interpersonal dynamics in favor of strategic execution.