The "Harbinger" in Doctor Who refers to entities whose role is to announce or herald the arrival of gods from the Pantheon of Discord, a group of powerful and often chaotic gods within the Doctor Who universe
. These harbingers appear as various characters linked to specific gods, serving as their messengers or signs of their impending arrival. For example, in the Fifteenth Doctor’s era, the character Mr. Ring-a-Ding is revealed to be a harbinger of Lux Imperator, the god of light and a member of the Pantheon of Discord. Mr. Ring-a-Ding appears as a 1950s-style cartoon character who comes to life and reveals his true identity as Lux, who uses illusions and film reels to trap people and feed on light
. This character is part of a recurring theme where each god in the Pantheon has a harbinger associated with them, although some fans speculate whether there might be a singular harbinger aligned with the top god rather than one for each
. Harbingers are often mysterious and may not be fully "real" people but rather mystical beings that form to signify the coming of their god. Their names sometimes follow a pattern like "H. Arbinger," which could be a form of nominative determinism to communicate their purpose to humans
. In summary, harbingers in Doctor Who are mystical entities that serve as heralds or signs of the arrival of powerful gods from the Pantheon of Discord, often appearing in forms that blend the eerie and the surreal, such as animated characters or enigmatic figures connected to the gods' influence
