Kiriha is a tsugumomo, a spirit that inhabits an object that has been cherished for many years. Her true form is a hand-woven, pure silk obi, or kimono sash, featuring a sakura cherry blossom pattern. As an obi, her potential for combat is highly dependent on the spiritual power of her owner. When in human form, her appearance changes based on her owner and her available power; she generally appears as a young girl with long, light blue hair, red eyes, and pointed ears, retaining the faint scent of cherry blossoms.

Kiriha displays a personality that is as multifaceted as her weaving techniques. She is often boastful, self-centered, and eccentric, acting on impulse with little concern for consequences. She is bossy and prefers to be in charge, disliking following orders from others and expecting those around her to cater to her desires, sometimes through forceful means. Her daily life is marked by laziness and self-indulgence; she spends her free time dozing, watching television, or playing video games, with a particular fondness for RPGs. Above all else, she has an extreme love for sweets, especially pudding, which is the one thing that can reliably motivate her to follow instructions.

Despite her selfish and abrasive exterior, Kiriha is defined by a deep and unwavering loyalty to those she cares for, willingly risking her own life for them. She takes her duty of destroying malevolent spirits called amasogi seriously, becoming focused and reliable in battle. Furthermore, she is compassionate, doing her best to exorcise an amasogi without destroying it to prevent its human host from suffering Curse Backlash. Another of her most notable traits is her complete lack of shame regarding nudity and sexual topics, which she discusses openly and uses to tease more prudish individuals like Kazuya and the deity Kukuri. However, this brazenness is tempered in the presence of more assertive people, such as her former owner Kanaka Kagami, towards whom she becomes more submissive and passive.

Her background begins as a family treasure named Ayasakura, passed down for generations by the Hanamitani cloth sellers until she transformed into a tsugumomo for the young Nui Hanamitani. The two were companions for decades until Nui passed away at the age of one hundred and five. Following Nui's will, Kiriha was sent to the Tsuzura Temple to be paired with a new exorcist. There, she was chosen last by a young Kanaka Kagami, who saw potential in the seemingly non-combative obi. Together, they became a formidable team, with Kanaka drawing out Kiriha’s full power. During this time, Kiriha lived with Kanaka, witnessed her marriage to Kazuaki Kagami, and helped raise her children, Kasumi and Kazuya.

Kiriha’s central role in the story is as the primary partner and protector of Kazuya Kagami. When Kazuya was born with immense spiritual power, he was made the owner of Kiriha to suppress his abilities, a transition that caused her to take on a younger appearance. After a traumatic event involving his mother, Kazuya's memories were sealed, causing him to forget Kiriha. Without his memory, she lost her power and reverted to an ordinary obi for years. She is reawakened when an amasogi attacks Kazuya, and she becomes his mentor, protector, and weapon as they combat supernatural threats together.

Her key relationships are central to her character. Her partnership with Kazuya is complex, beginning with her declaring him her servant and often treating him with violence and contempt, but this masks a deep-seated need to protect him from the trauma of his past. Kiriha has a deep respect and loyalty for Kanaka Kagami, who was the first to truly believe in her abilities, and she carries the heavy burden of having been forced to kill her former owner. She also has a long-standing, competitive, and teasing friendship with the local deity Kukuri. With Kazuya’s sister Kasumi, Kiriha shares a household, and Kasumi is one of the few people who can stand up to her without being intimidated.

Throughout the story, Kiriha undergoes significant development. She starts as a tsugumomo who resents being treated as a tool, a hatred born from her desire to be seen as a partner. Her relationship with Kazuya forces her to evolve from being a dominant, controlling protector into a true partner, especially after Kazuya declares his intention to protect her. Her past actions and the sealed memories create constant tension, and her eventual sacrifice for Kazuya leads to her being forgotten again, a fate akin to death for a tsugumomo, before she is eventually revived.

Kiriha possesses a versatile and powerful set of abilities known as Weave Techniques, which involve manifesting layers of her obi body and weaving them into various forms for combat, defense, and mobility. Her fundamental techniques include Obi Jab to strike, Obi Bind to restrain targets, and Obi Wheels for fast travel. For defense, she can create Shield Weave to block attacks and her ultimate defense, the Fence Weave Inner Court Formation, a multilayered barrier that can withstand extremely powerful assaults. Her offensive arsenal includes the Hammer Weave for crushing blows and the Spear Weave for piercing. Her signature attack is the Spiral Weave, a powerful drill-like technique that can be enhanced with her owner's spiritual power, as seen in the Core Excitation Spiral Weave. She can also use the Feather Weave to form wings for flight and the Muscle Enhancing Weave to augment her user's physical strength and grant techniques like the Coiling Snake punch. The full range of her abilities demonstrates her incredible ingenuity and adaptability in battle.