The Black Knight is a character and boss in Sly Cooper: Thieves in Time.
When the Cooper Gang first arrived in Medieval England, they didn't know much about the Black Knight. The only thing they did know was that he was running the show in that time period, and he managed to humiliate Sir Galleth Cooper by making him a jester.
It wasn't until later on, during one of Bentley's jobs, that it was found out the Black Knight was actually Penelope in a suit of armor. Her reason for helping out Le Paradox was money, as well as letting Bentley know that he was letting Sly take all the credit for his hard work.
She upgraded her Black Knight into a much larger version, complete with missiles and lasers. In the end, she was defeated by Sly, as well as Bentley. She got arrested and eventually broke out of jail, remaining at large.
