The Great War was a fierce conflict between the Lombaxes and the Cragmites that occurred in the Polaris Galaxy eons before the series, eventually resulting in the disappearance of both races from the universe.
The Cragmites had formed an empire that had taken over most of the Polaris Galaxy and caused most planets to fall under their tyrannical rule. The Lombaxes knew that something had to be done and engaged in combat with the Cragmites. Both sides were evenly matched and the war soon became a stalemate, with neither race gaining an advantage over the other. Notable people who fought in the war included: Zorthan on the side of the Cragmite Empire, and Cronk and Zephyr on the side of Allied Polaris.
In order to end the Great War for good, the Lombaxes assembled 8 of the greatest minds they had and created the Dimensionator, a device capable of sending the Cragmites to another dimension. The Cragmites were banished from Polaris and their empire finally fell, leaving their home planet of Reepor a dormant wasteland. Because of the power of the Dimensionator and what it could do in the wrong hands, knowledge thereof was kept secret among the Lombaxes and left many races believing that the Cragmites had been vaporized because of their sudden disappearance.
Many eons after the Great War, Lombax trillium miners on the Kreeli Comet found a frozen egg in one of the mines. Despite the fact it was a Cragmite egg, the Lombaxes decided to raise it as one of their own. Percival Tachyon would live the majority of his life not knowing of his race's legacy until the fateful day he found out. Furious at the Lombax race for not telling him of the Cragmites, Tachyon left Fastoon and began to amass his armies for an attack. After a while, Tachyon returned under the guise of an inventor and managed to persuade Lombax Elder Alister Azimuth to give him access to Lombax technology. Tachyon then attacked Fastoon, killing and injuring many Lombaxes. The survivors barricaded themselves in the Court of Azimuth and used the Dimensionator to escape to another dimension.
The Polaris Galaxy once again fell under Cragmite rule, leaving the Dimensionator's Keeper Kaden, his infant son, Angela Cross and Alister Azimuth as the only known remaining Lombaxes in the universe after the war. Kaden sent Ratchet to Planet Veldin in the Solana Galaxy to keep him safe. Kaden was later killed by Tachyon, Angela was sent to Planet Grelbin in the Bogon Galaxy to escape from Tachyon's persecution, and Azimuth later died trying to use the Great Clock to save the Lombaxes.