Sanada commands loyalty as the Valhalla royal family’s chief maid, sporting dark blue hair and feline traits befitting her catgirl identity. Upon detecting Valkyrie’s presence on Earth, she relocates to Kazuto’s residence, promptly acknowledging him as the princess’s fiancé despite Valkyrie’s shift to a childlike form, which she deems charming. Her signature "Cat Ear Gun" brainwashes perceived threats into obedient catgirl maids, inadvertently spawning permanent armies that retain their altered appearances and subservient mannerisms even when not summoned.

Driven by an unyielding focus on Valkyrie’s safety and romantic prospects, her aggressive tactics—such as forcibly transforming rivals—often amplify conflicts, triggering city-scale destruction during counterinterventions. Despite her rigid professionalism, she harbors a mischievous flair, dubbing herself a "Valkyrie fundamentalist" and adopting a temporary superhero persona to aid protagonists in later arcs.

Subtle plot threads link her to "Valkyrie Ghost," an enigmatic entity from Valhalla’s history, though their connection stays ambiguous. Over time, her role expands from comedic obstructionist to earnest ally in crisis resolution, all while maintaining her foundational devotion and fervent, if excessive, commitment to her duties.