Hisae Hasegawa is the wife of the main protagonist, Heizou Hasegawa. Her background is explored through her connection to her husband's past, revealing that she was a childhood neighbor to both Heizou and a man named Kanshirou Kondou. In her youth, she was romantically involved with Kondou, a relationship that led to a scandal when she gave away her honor to him. This event left her future uncertain and potentially untenable. It was Heizou's decision to marry her that ultimately saved her from that difficult situation.

As a character, Hisae is portrayed as a good-willed, attentive, and empathetic woman. She is frequently shown to be concerned and caring, especially when discussing troubling matters with her husband. Her personality is central to her role within the Hasegawa household, where she acts as a steady and compassionate presence. Her past has given her a personal understanding of mistakes and redemption, a quality she shares with her husband, who is known for not judging people too harshly for their past transgressions.

Hisae's primary role in the story is to manage the domestic sphere, allowing a glimpse into Heizou's private life away from his duties as a feared crime commissioner. She is a regular, though often minor, character. She is responsible for the day-to-day care of their mischievous adopted daughter, Ojun, who is the child of a thief that Heizou apprehended. Hisae's patience is tested by Ojun's behavior, and her development as a character is shown through her growing understanding and acceptance of the girl, particularly as she learns more about Heizou's own difficult and rebellious youth. She is also the mother of their biological son, Tatsuzou.

A key moment of development for Hisae occurs when the figure from her past, Kondou, resurfaces. She receives a letter from him and goes to meet him alone, an event that forces her to confront her history. In this instance, she shows courage and a willingness to face her past in order to protect her family, even if it means her secret will be revealed. The narrative confirms that Heizou is already aware of her past and does not hold it against her, reinforcing the foundation of trust in their relationship. In an original video animation focused on Heizou's early days, Hisae's perspective is also sought by a young man investigating the commissioner's past, confirming her role as a confidante who holds intimate knowledge of her husband's life.

Her notable abilities are not related to combat or investigation but are instead personal and relational. Her primary strength lies in her empathetic nature and her role as the emotional center of the Hasegawa home. She provides a sense of normalcy, warmth, and moral support, serving as a confidante for Heizou and a mother figure to Ojun. Her past as a "bad girl" has given her a nuanced perspective on life, which contributes to her non-judgmental and caring demeanor.