Master/Sayaka, a cunning con artist, runs Café Hako-bune as a front for her income-generating schemes. Orphaned with a foreign grandfather, her Western features fueled past acceptance struggles. Renowned for sharp business acumen and opportunism, she orchestrates insurance frauds, marriage swindles, and stock manipulations, prioritizing profit through a pragmatic, cynical lens.

Her rapport with café staff intertwines exploitation and mentorship. She recruits Arashi, Hajime, and Jun, exploiting their unique talents—time travel included—to salvage expired goods or retrieve lost items, incentivizing them with sweets and favors. Though manipulative, sporadic concern surfaces through advice or tolerance of quirks, cultivating a domineering older sister dynamic.

She habitually drowns in beer during solitary nights, enduring regular hangovers. This alcoholism dovetails with overlooking food expiration dates, forcing staff to avert health violations. A perpetual cigarette and apron draped over bare skin cement her brash, unapologetic image.

Unrequited love for Takeshi Yamashiro gnaws at her, his apathy stoking frustration. She vies for his notice but falters against rivals like bespectacled Kanako, whose presence eclipses her endeavors. Antagonism defines her clashes with PI Hideo Murata, whose disruptions she counters with cunning—like framing him mid-motorcycle race.

Subtle vulnerabilities surface through keen observation of staff emotions, occasionally nurturing growth—like prompting Jun’s identity confrontation. Her past whispers unresolved ties to elderly Sogoru, his role unclear. Though profit-driven, sporadic leniency—alternative compensations for damages—reveals a layered morality beneath her opportunistic veneer.