A member of an American family of Enjutsushi, who are specially skilled in creating and controlling spirit beasts to harness flames. She originally came to Japan to defeat Ayano and take her family's sacred treasure Enriha, but decides to stay after a crushing defeat by her. She develops feelings for Kazuma after he trains her for her second fight against Ayano. She manipulates myriads of spirits into a single virtual persona to grasp tremendous power. While seemingly capable of creating different spirit beasts, her favorite is Metatron, an angel-like statue equipped with a sword. Kazuma has observed and mentioned that her fighting style is similar to Ayano's, referring to their simplistic and direct attacks, which lack any strategy or tactics. A rival against Ayano in both Enjutsushi and Kazuma's "love", Catherine refuses to be beaten in either.
Catherine has long curly blonde hair and blue eyes. She wears a long frilly red dress with black accents and has a red rose in her hair.