Hinami Fuegucho is a young ghoul whose life is profoundly shaped by tragedy and the loss of her family. Both of her parents were killed by ghoul investigators, an event that becomes a central driving force in her story. Initially introduced as a shy and gentle child with a deep love for reading, she struggles with profound sadness and depression following the death of her mother, Ryouko Fuegucho.

Hinami’s need to learn and her fascination with books become key aspects of her personality. She has a great thirst for knowledge and is often seen studying, with Ken Kaneki acting as a mentor figure who teaches her new words and characters. Over time, the hardships she endures cause her to adopt a more grounded, realistic, and sometimes hardened worldview. She comes to accept the brutal realities of being a ghoul, such as dealing with death and the need to become stronger to protect those she cares about, determined not to lose anyone else important to her.

Her role in the story evolves significantly as she moves from a protected child to an active participant. After Kaneki leaves the Anteiku coffee shop, Hinami joins his group to uncover the truth about Rize Kamishiro and find Doctor Kano. Later, following Kaneki’s disappearance, she joins Aogiri Tree, an organization where her exceptional talents in combat and perception lead to her becoming one of its leaders, known under the alias "Yotsume". During this time, she works alongside Ayato Kirishima. She is known to the CCG as Subject No. 745 and the "Ghoul Daughter". Key relationships define her actions; she shares a powerful bond with Touka Kirishima, who promises to protect her, and remains deeply loyal to Kaneki, whom she views as a brother or teacher. This loyalty leads her to join Aogiri Tree primarily to locate him.

Hinami is a physically small teenage girl with light brown hair and brown eyes, and she is easily identified by her signature hairband decorated with two four-leaf clovers. As she matures, her hair darkens and her style becomes more strictly feminine, often wearing light shirts and dark skirts. She is an exceptionally rare ghoul who has inherited the kagune, a ghoul's predatory organ, from both parents, giving her a hybrid type usually not seen in a single individual. From her mother, she inherited a Koukaku kagune which takes the form of hard, wing-like or petal-shaped shields perfect for defense. From her father, she inherited a Rinkaku kagune, manifesting as powerful tentacles used for offensive attacks, which can evolve to produce up to four limbs. In combat, she strategically combines these abilities, using the Koukaku for defense and the Rinkaku for devastating attacks. The main drawback to this combination is reduced mobility due to the heavy nature of her Koukaku. Complementing her combat skills are her extraordinarily sharp senses, particularly her sense of smell and hearing, which even surpass those of ordinary ghouls and allow her to detect enemies from great distances or through obstacles. Proficiency in using both of these kagune types from a young age makes her an exceptionally powerful and skilled fighter. Her journey is marked by a profound transformation from a grieving, innocent girl into a formidable and resilient warrior shaped by loss and a fierce need to protect her loved ones.