Benika Jūzawa is a professional dispute mediator, often referred to as a "solver," who operates at the highest levels of her dangerous profession. She is the employer and benefactor of the series' protagonist, Shinkurō Kurenai, having rescued him after his family was killed when he was a child. Following this traumatic event, she took responsibility for his future, arranging for him to be trained in martial arts by the Hōzuki family and setting him on the path to becoming a mediator himself. Her decision to save and mentor Shinkurō was not based on calculation but on a spontaneous intuition, a quality she trusts implicitly as it has never failed her.

In terms of personality, Benika is calm, collected, and highly spontaneous, often acting on her instincts rather than elaborate plans. While she projects an image of a cool and nearly invincible professional, her personal life is far more complicated and marked by a distinct crookedness, especially concerning family matters. She is the mother of a son named Jūzawa Jū, but her relationship with him is severely dysfunctional. Her love is predominantly expressed through extreme violence and physical abuse, leading her son to both fear and resent her. This behavior is suggested to be a twisted attempt to drive him away from her violent world, though the effect is deeply damaging. Despite this harsh exterior, she does harbor genuine affection for her son; she nurses him when he is injured and has stated she would cry if he were to die, revealing a layer of love buried beneath her brutal methods. She also seems to view Shinkurō as something akin to an adopted son.

Benika's primary motivation in the story is to fulfill a promise made to the dying mother of a young girl, Murasaki Kuhoin. Acting on this promise and her own intuition, she kidnaps the seven-year-old Murasaki from the oppressive Inner Sanctuary of the powerful Kuhoin family. To protect the girl and allow her to experience the outside world her mother wished for her, Benika entrusts Murasaki into the care of Shinkurō, believing he is the right person for the job. In this way, Benika serves as the catalyst for the entire plot, setting her protégé and the young heiress on their path together.

Her role in the story is that of a powerful, almost legendary figure who operates from the shadows. She is Shinkurō's employer, his savior, and the standard of strength to which he aspires. As a solver, she is described as being among the strongest in the world, with a reputation that is widely known and feared. While she often works as a duo with the formidable Yayoi Inuzuka, her own abilities are extraordinary. In the original source material, she is a master of firearms, wielding pistols with deadly accuracy and wearing a bulletproof coat, and is capable of incredible feats like fighting a high-ranking opponent and taking one of their eyes. In the anime adaptation, her combat style is portrayed as less reliant on guns and more focused on unarmed hand-to-hand fighting, though she remains a highly skilled and formidable fighter. Regardless of the medium, she is characterized by her overwhelming power, which leaves a lasting impression on everyone around her, particularly Shinkurō, whose entire career is a tribute to her strength.