War of Wrath

The War of Wrath was a conflict that took place on Cybertron prior to the Golden Age.

Transformers: Exodus
The was fought between the Quintessons who had long occupied the planet and dominated its inhabitants and the Cybertronians who rose up against them. The war ended with the expulsion of the Quintessons from Cybertron, something that the Quintessons never forgot or forgave.