Zandrias, who adopts the human alias Sachiko Dori, is a kaiju-human hybrid distinguished by lilac hair, crimson eyes, and a petite, youthful frame. Bearing the soul of the primordial kaiju Zandrias, she shares this inherited lineage with her mother, a fellow hybrid. Frequent clashes with her mother fueled her defiant demeanor, culminating in her fleeing home and unleashing chaotic destruction in her volatile kaiju state. Benio Utagawa, a seasoned operative of the organization GIRLS, quelled these rampages and subsequently mentored her as an apprentice.

Though initially resistant to affiliation, Sachiko slowly acclimated to GIRLS through disciplined training, her rebellious streak enduring despite progress. A pivotal bond formed with Misao Otonashi led them to establish a rock band, though their anticipated concert was thwarted by an assault from Shadow Guts—a force tied to another GIRLS member—disrupting their ambitions.

In kaiju form, Sachiko wields functional wings for aerial mobility and can exhale searing flames. Her evolution traces an unsteady path toward self-mastery and maturity, suggesting growth beyond mere defiance as she navigates GIRLS’ structure. Tensions with her mother linger as a narrative thread, though the precise trajectory of their relationship remains unexplored.

Her story centers on reconciling dual identities, clashing with familial legacy, and balancing fiery independence with the demands of collective duty, all framed within her integration into a regimented world.