Oh, yeah, she's my pet. Yuj found her and brought her home.Serah tells Noel of how she came across Snow
Possibly due to being named after Serah's fiancée, in at least one cutscene in Final Fantasy XIII-2, Snow is referred as a male.
- Mog Trivia
Snow is a stray cat that Yuj found, kupo! Gadot was just joking when he said they should call her Snow, but the name stuck and that was that.
But in fact, everyone in the town has their own name for her, such as Esmeralda and Mewmew. It's one thing to call a girl cat 'Snow,' but when you give her a dog name like Spot, that's just wrong, kupo!
—Sparkling Runestone fragment.
One day Yuj found a stray cat and brought it to NORA House and asked if they could keep her. There were no objections and the cat approached Serah, making her smile.
After finally catching her, Serah tells Noel Snow's backstory and reflects the loss of her sister, Lightning, and her fiancee, Snow Villiers, "how [NORA] saw right through her", and how they keep together to keep strong in tough times. Noel asks if she considers them a family. If the player answers "The cat is my only family!", Serah will remark on her affection towards the cat.