First Cybertronian Civil War

The First Cybertronian Civil War is a historical event from the IDW portion of the Generation 1 continuity family.

Before the more well-known Great War, Cybertron first became a place of battle during the First Cybertronian Civil War.

Fiction

IDW Generation 1 continuity

After the departure of the Knights of Cybertron, Cybertronian society splintered into the Thirteen Tribes, each led by one of Thirteen warrior-leaders born as Primes. 10 million years before the present day, divisions among the tribes escalated into open warfare.

According to Nexus Prime, the war began when Megatronus Prime joined Liege Maximo to betray Solus Prime. The Crucible Regardless of however it began, the war spread across space, reaching planets such as Spindrift. Heart of Darkness #3

Nexus Prime formed an alliance with Onyx Prime, using his Enigma of Combination to create the Headmasters, fusions of humanoid and beast-form Cybertronians. Megatronus's former servant Galvatron, however, saw the Headmasters as abominations, dilutions of Cybertronian "purity". On day 43 of the Battle of Aegiax, he entered the fray, single-handedly slaughtering the Headmasters, The Mind Bomb and becoming a renowned war hero. Shockpoint Afterwards, Alpha Trion, last of the Thirteen on Cybertron, approached Galvatron and offered to bestow everything that he ever wanted. The Mind bomb Galvatron then continued fighting the Headmasters all the way to the headquarters of Nexus Prime himself. Despite the notion that only a Prime could kill a Prime, Galvatron slew Nexus with ease. This revelation caused the rest of the Thirteen to flee the planet, though everyone else besides Galvatrion and Trion would remain unaware of why. Galvatron took the Enigma and shot it off into space in hopes that no more combiners could ever come into existence. The Crucible

As Prima was now gone, leadership of his forces fell to Nova Major. He led the remainder of Prima's tribe, including his subordinate Eucryphia against a siege by the bestial hordes of Onyx Prime. However, Nova was left standing as the last defender of the Citadel of Light until Galvatron arrived from the wilderness at the direction of Trion and joined Nova. Together, they emerged victorious and turned the Siege of the Citadel of Light into a byword for courage. Afterwards, Alpha Trion revealed himself as the one who had brought the two of them together. He accepted that the era of his brethren was past and explained that he had brought Nova and Galvatron together so that they could end the war and bring about peace to Cybertron. The Crucible With Trion's blessing, Nova took on the mantle of "Prime" and unified the planet, ushering in the Golden Age. Primus: All Good Things