Hinami Fueguchi is a young ghoul who becomes a significant figure within the world of Tokyo Ghoul. Initially introduced as a shy and gentle child, she is the daughter of two ghouls, Asaki and Ryouko Fueguchi, who were both killed by ghoul investigators from the Commission of Counter Ghoul. Following these tragic events, she finds a new family and sense of belonging at the Anteiku coffee shop, where she forms deep and lasting bonds with Ken Kaneki and Touka Kirishima.

In her early appearances, Hinami is characterized by her timidity, her gentle heart, and a strong eagerness for knowledge. Unable to attend school due to her nature as a ghoul, she develops a love for reading, particularly the works of the author Sen Takatsuki. Kaneki becomes her informal tutor, helping her understand complex words and fostering her intellectual curiosity. Despite the violent death of her parents at the hands of investigators, Hinami displays a remarkably pacifistic nature, expressing sorrow rather than a desire for revenge. She struggles with the loss of her family, asking Kaneki if it was right for her to continue living, but ultimately chooses to honor her mother's wish for her to survive.

Her primary motivations shift from personal survival to a deep-seated desire to protect and support those she loves. She cares for Kaneki and Touka as if they were her own siblings, often worrying about their unhappiness and feeling helpless when she cannot ease their pain. This devotion drives her actions, including her decision to join Kaneki’s independent group after the Aogiri Tree arc, as she could not bear to leave him alone.

As the story progresses into Tokyo Ghoul:re, Hinami undergoes significant development. Following the devastation of the Anteiku raid and Kaneki's apparent death, she joins the Aogiri Tree organization. Her primary goal is to locate Kaneki, believing he might still be alive. Within Aogiri, her demeanor becomes more calm, collected, and distant, hardened by her experiences. She takes on a more active and strategic role, utilizing her exceptional abilities as a scout, information analyst, and field commander under the alias Yotsume. Despite this tougher exterior, she remains reluctant to kill, viewing this reluctance as a personal weakness.

Key relationships define her character arc. Her bond with Touka Kirishima is that of sisters, with Touka acting as her fierce protector and Hinami offering unwavering loyalty in return. Her relationship with Ken Kaneki is central; he is the "big brother" figure who gave her a reason to live and a love for learning. In Tokyo Ghoul:re, she recognizes Kaneki even when he has lost his memories and become Haise Sasaki of the CCG, tearfully declaring that she will protect him and will not let him fight alone anymore.

Hinami possesses notable abilities that make her exceptionally powerful for her age. She is a natural chimera, having inherited both of her parents' kagune, a rare occurrence among ghouls. From her mother, she inherited a Koukaku kagune that takes the shape of petal-like shields on her shoulders, which she uses for defense. From her father, she inherited a Rinkaku kagune, which emerges from her waist as powerful, spine-like tentacles used for long-range, high-speed offense. This dual-kagune combination makes her a formidable fighter. Complementing her physical prowess are her extraordinary senses. Her sense of smell is so acute that she can detect enemies from a great distance and even identify the unique scent of a half-ghoul like Kaneki. Her hearing is equally remarkable, allowing her to analyze multiple audio streams simultaneously to extract critical information.