I don't think the word "demon", or even "Dæmon", appears in The Satan Pit. I'm not 100% if "evil" is either, but the description of the Kaled god of war and Earth, Dæmos and Draconia's "horned beasts" in Pit absolutely doesn't use any variant of "evil creature" or "evil god". Are devils and fallen angels even considered "gods"? They're almost certainly not in real-world Judeo-Christian religions. The Dæmons uses the term "demon" but barely and in no depth beyond the context of the Dæmos species of Dæmons.
The Master was seen to humans as a demon when his form was comprised solely of energy. He used demonic powers such as possession to find new hosts for his dying form. (PROSE: Prologue)
The Dæmons were a race of advanced aliens from Dæmos. During their travels on Earth, they probably influenced the mythology of the native humans. (TV: The Dæmons) They themselves had a figure in their mythology similar to the Beast. (TV: The Satan Pit)