Casey appears to be medium height, perhaps 5'7' or so, with a long, oval face, a lot of curly ginger hair, and a slender build. She also appears to be younger, perhaps in her mid-twenties.
Her werewolf form is relatively short for a werewolf, looking to be less than seven feet tall. When transformed, her fur does not completely match her hair color. She has light brown fur mixed in with patches of red. She has a mass of curly ginger-red hair on her head, even as a werewolf.
Her demeanor appears to be somewhat timid. She doesn't seem to handle Tom's outburst as well as the others do, possibly due to her relative youth.
She and the rest of the Yardley Pack came over from Ohio, helping Thomas in his effort to claim Crescent Lake.