Note: Katrina is Kitty's only sibling in Hockeyben's T.U.F.F. Puppy world. Kitty does not have a sister in jail, and the other fan-made Katswell siblings are not of relation to her.
Katrina Katswell (often referred to as Kat Katswell) is Kitty's younger sister. She is four years younger than Kitty.
Katrina joined T.U.F.F. when The Chief offered her a position after she graduated from Secret Agent College. Like Kitty, she is skilled in combat, and holds a black belt in Karate.
She bears a strong resemblance to Kitty, but has brown eyes instead of green, and stands 5'5", making her an inch-and-a-half shorter than Kitty. She has the same jet black hair as her sister, but she wears it slightly differently.
Katrina looks up to Kitty, and the sisters have a tight bond.
Much like her sister, Katrina was (and still is) at odds with Mrs. Katswell.
Katrina gets along well with Dudley, and finds his company enjoyable.
Katrina is very obedient to The Chief, and thinks of him as a great leader.
She is good friends with Keswick, but generally spends more time with Kitty and Dudley.