Great Cragmite Empire

The Cragmite Empire was originally the greatest threat in Polaris as the Cragmites held unstoppable power at their disposal. The Lombaxes eventually defeated their empire, freeing Polaris. By comparison, Emperor Tachyon's Imperial Empire is the merest shadow of the once allmighty Cragmite Empire.

Great War
During the Great War the Cragmites inhabited Reepor and quickly took over Polaris using a large army and unstoppable force. The Lombaxes eventually defeated them by creating the Dimensionator and using it to send them to another dimension during their final battle on Reepor. Despite all of the Cragmites being trapped in another dimension, Percival Tachyon had survived due to the fact that he was frozen as an egg on the Kreeli Comet and later discovered by the Lombaxes. They raised him out of pity on Fastoon.

Tools of Destruction
In Ratchet & Clank Future: Tools of Destruction Tachyon rules over Polaris in the replacement of the Cragmite Empire, his Imperial Empire. He eventually finds the Dimensionator and uses it to bring back the Cragmites, who follow Tachyon in reconquering all of the galaxy under the rule of the Cragmite Empire. Ratchet, Clank, Talwyn, Cronk, and Zephyr defeat Tachyon and his armies, though he may still be alive and the Cragmites presumably have reinhabbited Reepor, meaning that the Cragmite Empire will most likely rise again.