Penelope "Penny" Ares was a character in the seventh season of The Vampire Diaries. She made her first appearance in Things We Lost in the Fire, when she arrested Matt for drunk-driving.
After the three year time-jump, it has been revealed that Penny was killed at some point (and originally thought to be killed by Stefan Salvatore), which is the main reason why Matt agreed to work with Rayna to try and bring Stefan down. It is revealed that she got engaged to Matt Donovan shortly before her death. However, it is revealed that Matt accidentally shot Penny while hunting down Stefan.