(warning : the following article will likely become very long due to its nature, however it play a crucial role in understanding the mythos of the series and is directly linked to many villainous events and characters in both Buffy, Angel and Spike lore - all of which are known collectively as the "Buffyverse").
Demons are malevolent extra-dimensional beings that make up a sizeable portion of the Buffyverse villain gallery, they are related to Vampires but are considered a host of many related species rather than a single species - some species of demon are peaceful but the vast majority are considered a spiritual evil and have been in conflict with humanity (and even vampires) for countless centuries.
It is the role of the Slayer to weaken the forces of darkness, which are often led by demons of high ranks and even a minor demon is often considered a more formidable foe than the average vampires (excluding, of course, Master Vampires, who are often as powerful (if not more) than a minor demon).
Major Demonic Species
- Lubber Demons (a society of demons that believed in the destruction of humanity)
- Gentlemen (although not officially considered demons these "fairy tale" monsters shared many traits of demons in Buffy lore)
Major Demonic Characters
- The Judge (an ancient demon brought back to life by Spike and Drusilla, sought to destroy humanity)
- Moloch (a medieval demon who lives on via the internet in the modern age (due to a mistake by Willow) )