Cathy has an obsession with cats to the extent that she behaves like them and can control them. Cathy is a loner and a stereotypical shy girl, especially towards her crush; Yuma Tsukumo. As stated above, Cathy has a bizarre obsession with cats and seems to have an affinity for controlling them. Her obsession goes to the point that she decorates almost the entire interior of her house with cat-themed paraphernalia. She has a habit of dressing up in cat-themed clothes in the Gothic Lolita style and sometimes exhibits cat-like behavior; i.e. curling her hands to simulate cat paws, finishing her sentences with the word ニャーnya and licking her lips.

(Source: Yugioh Wikipedia)