Sasana Shōsōin is a black-haired Cat God, or Nekogami, with striking grey eyes. Her engagement to fellow Cat God Mayu stems from an arrangement by their fathers, who deemed them a suitable match irrespective of gender. Typically composed and content, Sasana becomes notably enthusiastic and affectionate solely in Mayu's presence, consistently addressing her as "Mayu-sama" and expressing frequent eagerness for marriage. She wields a magical wooden sword called Swordfish, which transforms from a shamisen pick.

A fierce rivalry exists between Sasana and another Cat God, Meiko, due to their mutual affection for Mayu. This competition coexists with Sasana's deep-seated fear of losing Mayu, motivating protective actions such as intervening at a mangaka's residence to ensure Mayu's safety. Her dedication manifests through direct support in Mayu's endeavors, including aiding in the search for a lost jar of Blooming Ash essential for spring cherry blossoms and collaborating to confront and defeat the god of poverty.