General Staal referred to humans as beasts. (TV: The Poison Sky)
The Great Beast was a demon who identified as the Devil. (TV: The Impossible Planet / The Satan Pit)
On Trenzalore, the Great Intelligence claimed that "the Beast" would be one of the future aliases of the Doctor "before the end." (TV: The Name of the Doctor) As recorded by the Testimony, the "Beast of Trenzalore" was a name for the Doctor. (TV: Twice Upon a Time)