Catherine is an Amanto distinguished by cat ears and tanned skin, typically clad in a green kimono. Originally from the thief group Cat's Punch, she left for Earth and encountered Otose. Employed at Snack Otose, she landed in jail after stealing from Kabukicho establishments, including Otose's bar. Released, she vowed never to steal again and rejoined Otose, proving her dedication to change.

She speaks with an accent and displays fierce loyalty, exemplified when she tearfully stood outside Otose's hospital room for two days following an attack. Catherine frequently argues with the Yorozuya over unpaid rent but shares a warm rapport with Tama. Her exceptional burglary skills stem from extreme physical flexibility, specializing in bypassing locks and security systems. She breaks her no-stealing vow only once—in Episode 213—to kidnap a businessman’s son when Otose’s life and livelihood faced peril.

In "The Final" epilogue, Catherine appears aged, with a slightly shaved beard and a lower-pitched voice, her traditionally feminine traits diminished. This reflects time’s passage and her enduring residence in a transformed Edo. Her story closes with her remaining embedded in the Snack Otose community, highlighting her unbroken bonds with Otose and the Yorozuya circle amid societal shifts.