Knave of Hearts
From Tardis Wiki, the free Doctor Who reference
The Knave of Hearts was one of the deadly pawns used by the Celestial Toymaker against Steven Taylor and Dodo Chaplet when they were trapped in his realm. When not in a contest, the Knave stayed in playing card form.
He also appeared as the Kitchen Boy and Cyril. (DW: The Celestial Toymaker)
