Camilla is a worshipper of Chaos in early 19th centuryAustria, in the video gameCastlevania: Circle of the Moon, which is set in 1830. She is a demon who normally takes the form of a human, but when Nathan Graves fights her in a boss battle later in the game, she takes a different form. In the Japanese version of the game, her name is "Carmilla", which is probably a reference to the vampire novella, Carmilla, written by Joseph Sheridan Le Fanu (which was a strong influence for Bram Stoker's Dracula).
Camilla is a minion of Count Dracula, and in Circle of the Moon, she attempts to resurrect him. Camilla is eventually defeated by Nathan in his quest to rescue his mentor Morris Baldwin from the clutches of Count Dracula.
Camilla is also previously seen in Dracula X: Rondo of Blood as a major boss, assuming a few different forms, and in Castlevania II: Simon's Quest, in the form a flying mask that attacks the player with poison.