Hinako Saba is a young woman who initially appears as a wheelchair user, struggling with her mobility and trying to stand in a park, an act observed by the protagonist Akira Sato. Her circumstances are tragic, as she is under the control of the antagonist Utsubo Rei, who presents himself as a community activist but is in fact a ruthless manipulator and criminal. Hinako serves as one of Utsubo's subordinates, functioning as a secretary and investigator. However, her position is one of complete subjugation, as she is also used as a sexual slave by Utsubo and is kept in a doll-like, traumatized state, likely due to psychological conditioning and possibly drugs. Her backstory is deeply connected to the protagonist, as Akira recognizes her as the driver of one of his targets from a job he carried out four years prior, a connection that fuels the central conflict of the arc.

Despite her frail and compliant exterior, Hinako possesses a strong inner will that becomes evident as the story progresses. Her personality has been suppressed by years of abuse and manipulation, leaving her in a state of passive endurance. However, a pivotal shift occurs when she is forced into a situation where she is ordered to kill. When given a gun and told to execute Akira's partner Yoko as target practice, Hinako instead turns the weapon on Utsubo, revealing a hidden reservoir of defiance. This act of rebellion is driven by a crucial revelation: she has learned that it was Utsubo, not Akira, who murdered her parents. This knowledge breaks her conditioning and redefines her motivations, turning her from a helpless victim into an agent of her own revenge. The brutal manipulation she suffered from Utsubo is the key to her role in the story, as he uses her as the central piece of a trap to lure and eliminate Akira, the legendary killer known as Fable.

Her key relationships are defined by exploitation and unexpected connection. Her relationship with Utsubo is one of absolute predator and prey, marked by abuse and coercion. In contrast, her relationship with Akira Sato is more complex; he is the man who once caused the accident that led to her paralysis, yet he becomes an observer of her rehabilitation and ultimately a figure who inspires a dangerous hope. Akira sees her as a damsel in distress, a trope for which he has a noted weakness, and he instructs his partner to investigate her background, indicating his intent to intervene. Her relationship with Suzuki Hiroshi, Utsubo's experienced contract killer accomplice, is more ambiguous, as he is her warden and fellow subordinate, but his own crucial choices during the final confrontation ultimately affect her fate. The major development for Hinako is her transition from a passive victim used as bait to an active participant who chooses to defy her captor, culminating in a moment of trust where she relies on Akira to save her from a bomb trap set by Utsubo. Her primary notable ability is her resilience, having survived immense physical and psychological trauma. Beyond her role as an investigator, she has no superhuman combat skills, making her vulnerability—and her decision to fight back despite it—her most defining characteristic.