Master/Sayaka, a sharp-eyed opportunist, runs the café Hakubone as both a front and headquarters for her scams. Born to a foreign soldier grandfather, her Western features alienated her in youth, compounding the loneliness of early orphanhood. This forged her into a calculating survivor, chasing profit with relentless ingenuity. Her café staff—ghosts and living allies alike—double as tools for schemes, their supernatural skills repurposed: reversing food expiration via time jumps, manipulating events for her gain. Though she commands them with a domineering yet protective “older sister” air, flashes of genuine concern pierce her self-interest.

She routinely outthinks private investigator Hideo Murata, deploying tactics like luring police into illegal races to distract him. Her treasure hunts—aimed at quick wealth—often unravel humorously, yielding trivial items instead of legendary loot. Unrequited feelings for the refined Takeshi Yamashiro spark playful tension, mixing frustration with rivalry.

Exploiting the ghosts’ time-travel, she bribes spectral collaborator Kaja with desserts to aid her plots. Her dynamic with Hajime Yasaka oscillates between fiery disputes and fleeting alliances. A persistent café patron’s unanswered pleas for salt underscore her disregard for small annoyances amid grander ambitions.

Past cons—marriage fraud, stock market trickery, staged accidents—reveal a lifetime of adaptive deceit. Yet beneath her mercenary exterior lies sporadic introspection and subtle loyalty to her makeshift family, hinting at depths beyond her ruthless pragmatism.