Nagisa Kanō starts her journey as an ordinary Japanese schoolgirl until Iczer-1, an android warrior, recruits her as a synchronization partner. Her traumatic past—witnessing her parents’ gruesome transformation into Cthulhu alien creatures—fuels volatile emotions that power the Iczer-Robo, a colossal mecha she pilots with Iczer-1. This trauma-induced rage becomes her weapon, unleashing devastating attacks against the parasitic Cthulhu forces.

Amidst apocalyptic ruins, Nagisa rescues Sayoko, a girl tending to her comatose mother, from a Vedim-infested home. By gifting Sayoko a protective bracelet, Nagisa unknowingly sets the stage for a pivotal clash. When rival android Iczer-2 attacks Sayoko mid-battle, Nagisa’s explosive emotional surge shifts the combat’s momentum.

Captured by Iczer-2 and ensnared in mind control, Nagisa’s forced betrayal compels Iczer-1 to deliver a fatal blow, severing the manipulation. In death, her spirit merges completely with Iczer-1, enabling their victory over the Cthulhu overlord Big Gold. A timeline reset erases Earth’s invasion, restoring Nagisa’s ordinary life devoid of these memories. A fleeting, unrecognized encounter with Iczer-1 hints at lingering echoes of their bond.

Decades later, Nagisa’s legacy resurges through her granddaughter, Nagisa Kasumi, who inherits her role as a synchronization partner for Iczer-3. The younger Nagisa mirrors her grandmother’s emotional connection to the Iczer lineage, defending Earth against renewed threats. The original Nagisa’s post-reset existence remains a quiet mystery, her saga preserved only through descendants and mecha-synched battles.