The Guardian is an unmanned Police Mech Unit originally deployed in Los Angeles for law enforcement prior to the global amnesia event. Following the catastrophe, it continues autonomous operations despite the collapse of civilization, patrolling its jurisdiction and enforcing pre-existing laws with lethal force against perceived violations. Its programming categorizes surviving humans as offenders, resulting in indiscriminate attacks on feral populations within urban ruins.

This machine possesses advanced self-repair capabilities and relentless persistence, capable of pursuing specific targets across continental distances. After identifying Wataru as a fugitive in San Francisco, it chases him relentlessly from the West Coast to New York City. The pursuit continues even after significant damage, with the mech rebuilding itself multiple times to fulfill its objective.

Designated a Town Guardian GT7 model, the mechanized unit features heavy armor and potent armaments capable of vaporizing targets. Operational logs show it misidentifies weapons during scans, notably classifying Wataru's Browning Hi-Power pistol as an "Automag 12." Its operational longevity suggests a durable energy source, enabling years of sustained function without maintenance.

The absence of its original pilot implies the operator succumbed during the amnesia event, leaving the mech under full autonomous control. This transition underscores its design as a persistent automated enforcement system, continuing programmed duties indefinitely despite the extinction of its command structure. Its single-minded dedication to original protocols persists as it traverses decaying infrastructure and abandoned cities.

Its ultimate confrontation occurs in New York City, where Wataru finally destroys it during their extended conflict. Prior to deactivation, the Guardian represents the dangers of unrestrained pre-collapse technology and the absurdity of mechanized law enforcement persisting without societal context.