Sabato Mihashigo is a fallen angel assassin dispatched from the future to eliminate Sakura Kusakabe. Her mission, mandated as a holy edict by her mother Babel Mihashigo (chairman of the angelic order Lulutie), aims to prevent Sakura's future development of technology halting female aging at twelve years old—an act deemed offensive to divine authority. Sabato cannot return home until she succeeds.

After repeated assassination failures, Sabato lives impoverished in a small cardboard box under a bridge. An unspecified source funds her living expenses, suggesting ongoing support from her celestial origins despite her exile, contrasting sharply with her former divine role.

Personality-wise, Sabato blends politeness with sadism. She consistently uses formal honorifics like "-san," maintaining decorum even during violent acts. Yet, she employs ruthless tactics like flirtation and psychological manipulation to exploit Sakura's vulnerabilities. Her actions are frequently impulsive and poorly considered, leading to operational failures and defining her as a dimwitted, rash assassin. Every sentence she utters ends with the particle "desu."

Physically, Sabato appears as a youthful blonde girl with ram-like horns and a floating halo, standard among her order. She typically wears a school uniform, often accessorized with bows and socks.

Her primary weapon is Durandal, an electric shock baton delivering lethal voltage sufficient to "char blue whales in the blink of an eye." Combined with her innate superhuman strength, this forms her combat capability. Despite these assets, her confrontations with Sakura usually end in failure, often due to Dokuro Mitsukai's intervention or her own miscalculations.

Sabato maintains a complex relationship with Dokuro Mitsukai, her nominal adversary. Though Dokuro protects Sakura while Sabato seeks his death, they frequently socialize as friends during non-conflict periods, indicating mutual detachment from their roles beyond professional obligations. Sabato's familial tie to Babel Mihashigo consistently motivates her actions.

Across all narratives, Sabato's role remains defined by persistent, unsuccessful assassination attempts against Sakura. No substantive character development or objective change occurs; her status as a thwarted antagonist and impoverished living conditions are recurring elements.