Demon
Known to its modern population as Demons, Cybertron's original inhabitants were sealed away underground by Primus. Except for the occasional escape, they have remained sealed away by Primus's power ever since, known to the surface only in legends. According to those legends, the Demons are "the flipside of the Matrix's good creatures".
Demons are very large creatures (towering above Transformers) that can absorb energy without harm, up to direct weapons fire. At least one has demonstrated the ability to breathe fire. They "feed" on Transformers by absorbing their lifeforce, eventually killing them.
However, if a demon absorbs too much energy, it will explode.
Fiction
Marvel Generation 1 comics
Two of the Demons escaped from their prison following an incident between Tailgate and the Mutants. Some time after killing three Decepticons that beset the Autobot Seawatch, they were destroyed by Emirate Xaaron, who consulted ancient Cybertronian lore to find their weaknesses. Demons!
After Primus's death, another group of the Demons escaped, lurking in the shadows of Cybertron's surface after the giant battle against Unicron. As observed by Hi-Q, one of the Demons grabbed Runabout by the leg, dragged him underground, and messily devoured him. On the Edge of Extinction! Hi-Q fled until he encountered the Dinobots, whose considerable power was still not enough to defeat the Demons. They were finally beaten back by Grimlock, who had just completed his metamorphosis to an Action Master. The Demons fled from his new power, repulsed by his "light". Still Life!
Classics
When the Mini-Cons were created to clean up Cybertron, one of their jobs was to exterminate the Demons and Mutants. The Demons didn't go down without a fight, however, and Hacksaw would later express relief that no more Mini-Cons had to die by their hands. The New World
Notes
- The appearance of the Demons differs wildly depending on the artist.
- The Demons' origin resembles that of the Trans-Organics in some ways. Both races were built as precursors to the Transformers, but locked away by their creators.
- It is unclear in the stories if the Demons were the original inhabitants of the world Primus fashioned into Cybertron, or an attempt by Primus to create life that predated the Transformers. However, writer Simon Furman later clarified in an interview that he envisioned them as being botched creations of Primus.
