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 actions 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. If a demon absorbs too much energy, it will explode.

"Ourss before yourss, thiss world!"

- Demon

Marvel Generation 1 comics continuity
Cybertron's original inhabitants were sealed away underground by Primus.