|Minor Character: Las Vegas|
|Name||Catherine "Katy" Hill|
|Family|| Bo Mattison (father; deceased)|
Unnamed mother (deceased)
|Occupation|| Magician's assistant|
Serial killer (originally)
Spree Killer (later)
|Portrayed By||Natalie Hall|
|First Appearance||Last Woman Standing|
Katy's father was Bo Mattison, a high-stakes poker player who by 1997 was almost broke. That year he took part in the Palermo Poker Classic and played against three other poker experts, Ed Ficelli, Trent Alridge and Peter Coe. What he didn't know was that his opponents, led by Ficelli, and the card dealer were all in collusion to help each other beat him. Peter Coe finished him off. A week after losing, Bo killed himself in a park. Katy went on with her life until shortly after her mother died, when she found letters written by her father revealing that he figured out that he had been cheated. She planned to take revenge on the people behind the scam and took a job as an assistant for a stage magician named James Nefarro, a.k.a. "Dr. Jimmy", who had paid Peter Coe's entrance fee into the tournament.
"You want me to show you my cards?"
Katy targeted the people who had scammed her father. She killed them in widely-varying ways, each representing a card of the last five dealt cards on which her father lost.
- February 2013:
- Ed Ficelli (the ringleader; killed by a heroin overdose laced with trifolium, a.k.a. clover; represented "four of clubs")
- Trent Alridge (one of the players; asphyxiated by stuffing seven chicken hearts down his throat; represented "seven of hearts")
- Peter Coe (one of the players; slashed his throat by throwing a card at it; represented "ace of spades")
- Ava Rendell (born "Ava Heidbredder"; daughter of the dealer in the game; decapitated with a medieval warhammer; represented "king of diamonds")
- James "Dr. Jimmy" Nefarro (accomplice in the scam; attempted; represented "king of spades")
- Morgan Brody (attempted to shoot)