Chuutan is the Eto-shin of the Rat, holding the first rank among the twelve zodiac gods and standing as the most powerful of them all. She is tasked with protecting the region of South Kanto. Physically, Chuutan is tall with long, straight light purple hair and sharp red eyes. Her design features rat ears and a tail, along with three rhombus-shaped crystals on her forehead. Her usual attire is a purple bodysuit that leaves her abdomen exposed, accented with a yellow necklace, though this appearance changes later.

Chuutan has a personality that is fundamentally diligent, serious, and scrupulous, addressing all matters with sincerity. However, this surface-level maturity belies a much more complex inner world. In the distant past, she was known to be a warm, friendly, and approachable leader whom the other Eto-shin relied upon for support and guidance. This caring nature included a close bond with Nyaa-tan, a cat Eto-musume who was not part of the official zodiac. Over time, the heavy burdens of leadership and prolonged isolation began to foster intense negativity within her. Being genuine to a fault, she did not cast aside these dark feelings but accepted them, all while presenting a strong, unyielding front as an example to the others. This caused her stress and negative emotions to pile up internally, eventually corrupting her and transforming her into a merciless and cold individual with a deep-seated hatred for Nyaa-tan and the entire cat clan.

Her primary motivation becomes the destruction of Nyaa-tan, whom she perceives as a betrayer. This enmity is rooted in a past event where Nyaa-tan, attempting to save a corrupted Chuutan from herself, used a forbidden technique on her. From Chuutan's perspective, this act was a devastating rejection, making her feel like an obstacle that needed to be eliminated. She declares that her only purpose is to destroy the cat tribe, and she seeks out a confrontation with Nyaa-tan under strict new rules that forbid third-party intervention. In the story's narrative, Chuutan serves as the primary antagonist, representing the strongest foe that the protagonist must face. Her immense power is demonstrated when she effortlessly defeats over one hundred Eto-girls at once and poses a significant threat to the other Eto-shin.

Key relationships define her arc. Her bond with Nyaa-tan is the most pivotal, shifting from a deep, caring friendship to bitter rivalry, and eventually to reconciliation. Shaa-tan, the Eto-shin of the Sheep, also shares a significant connection with Chuutan, acting as her former mentor who maintains contact with her even during her dark period, worrying about her and providing guidance. Her conflict with Nyaa-tan comes to a head when the cat Eto-musume successfully uses the Kagura Senguu technique not to destroy, but to heal and purify Chuutan's corrupted Etotama, which is the source of an Eto-shin's power. Following this purification, the darkness leaves her, and her outfit transforms from purple to a pure white, symbolizing her return to her original, caring and soft-spoken nature. In a moment of vulnerability, she confesses to Nyaa-tan that her hatred was born from profound loneliness and grief over their separation.

Chuutan possesses several notable abilities. Her primary weapon is a red blade that can function as both a whip and a projectile. One of her signature techniques is Kokushi Tenchuusatsu, which unleashes a powerful, destructive red beam. However, her most formidable ability is the Kagura Senguu, a forbidden ritual-level technique that can only be performed by gods. This power is unique in that it has the capacity to either heal or completely destroy an Etotama. Chuutan learned this technique not through practice but simply by observing Nyaa-tan use it, mastering it to an extreme degree. She wields this fearsome power without hesitation, even knowing that the destruction of a single Eto-shin would upset the balance of all things in Japan. Her Skillful use of the Kagura Senguu is what led to Nyaa-tan's amnesia and fractured memories in the past.