Kinako is a small fox-cat hybrid creature known as a shikigami, a type of familiar spirit or servant, created by the exorcist Benio Adashino. As an anime original character, he was introduced to serve as Benio's companion following her traumatic experiences, and he appears regularly throughout the story. In terms of appearance, Kinako has white fur and bright orange-red eyes, and he is almost always depicted wearing a red scarf around his neck. The tips of his ears feature a red flame-like pattern, and his tail resembles a flickering orange flame.

In personality, Kinako is portrayed as energetic, vocal, and highly possessive of his creator, Benio. He is generally unfriendly and dismissive towards others, particularly Rokuro Enomoto, the other Twin Star exorcist, whom he sees as a rival for Benio's attention. Despite this abrasive exterior, Kinako is deeply loyal to Benio and demonstrates a caring and compassionate side, especially in his devotion to her well-being. He is also shown to be polite and even flattering towards authority figures, though this behavior is not always a reflection of his true feelings. Kinako is a sentient being, capable of self-reflection, and he has even questioned his own meaning and existence at points in the story. He becomes easily angered whenever he feels that Benio is being underestimated or disrespected by others.

Kinako's primary role in the narrative is that of Benio's loyal familiar and companion. He acts as a friend to her, especially in the early parts of her journey when she was more isolated and closed off from others. One of his key functions is to serve as an early warning system, possessing the ability to sense when Kegare, the malevolent spiritual impurities that are the main antagonists of the series, are about to appear. While not primarily a combat-type shikigami, he is considered a perfect shikigami by other powerful exorcists because he is able to maintain his own consciousness and remain utterly loyal to his creator. He also possesses vast knowledge about the world of exorcists and the setting of Tsuchimikado Island, and he is capable of performing decent housework.

Kinako's most important relationship is with Benio Adashino. The story reveals that he was given to her as a companion after a family tragedy left her traumatized. Initially, Benio was unresponsive to his attempts to befriend her and make her smile, but over time, she opened up to him, and they became inseparable. This backstory was explored in a dedicated episode that focused on how Kinako helped Benio heal from her loss, transitioning from a simple servant to a true friend. His relationship with Rokuro Enomoto is largely antagonistic, as Kinako is jealous and possessive of Benio, leading him to be vocal in his dislike for Rokuro and his role in her life.

Kinako's development is notable as he evolves from a character who could initially be perceived as a simple mascot or a one-note comedic device into a more fleshed-out and sympathetic character. Through episodes focusing on his backstory and his internal world, he is given depth, allowing viewers to see him as a devoted and stubborn servant who is willing to go to great lengths to protect his master's happiness and fulfill his duties. This development helps to transform him from a potential gimmick into a genuine supporting character with his own emotional arc.

Regarding his notable abilities, while not a frontline fighter, Kinako has several useful skills. His most frequently used ability is Impurity Detection, which allows him to sense the emergence of Kegare. He also possesses a technique called Kato Dai Setsudan, a simple slashing attack used to destroy targets. In the anime adaptation, Kinako is also shown to have the power to possess inanimate objects. For example, he can possess a truck, allowing him to control it and increase its utility in various situations.