Demon

As well as the alien Dæmons and other demonic beings, literal demons apparently exist, or at least beings described as such who conform to the description, without any alternative ones on offer.

One of these, Melanicus, stole the Event Synthesizer and briefly warped the Universe into his personal toy. (DWM: The Tides of Tide)

The Destroyer, unwillingly served Morgaine. The Destroyer had a vulnerabilityu to silver which enabled Morgaine to chain him with manacles made of it. When shot with silver bullets fired by Brigadier Lethbridge-Stewart, the Destroyed apparently died. (DW: Battlefield)

The Cardiff Rift bound Abaddon, named as a demon in the Bible. (TW: End of Days).

The beings had similarities. Both had horns, like the classical western conception of demons, also the Destroyer said he wished to "devour" Earth, while Abaddon absorbed life energy.

Other references

• In the court of King John I, the Doctor, Tegan and Turlough found themselves once mistaken for demons. (DW: The King's Demons)

• Demnos (DW: The Masque of Mandragora), rearranged around, spells demons.