People of the Feud

There was a colony ship, sent out from Earth or a world very much like it to settle a new world. It's navigators had been genetically modified to take advantage of a new drive system allowing FTL travel. The majority of the colonist were placed into cryogenic suspension for the voyage.

Something went wrong. Inadequate shielding? Purposeful sabotage? No one remembers. The navigators began to mentally breakdown, expose to psychoactive and mutagenic properties of the manifold outside normal spacetime. The ship was stranded stuttering in an out of spacetime.

The navigators began to develop psionic powers and with them certain physical requirements. Boosted quantities of certain neurotransmitters. No synthetic source was available, but there were the stored colonists to feed on.

To help them manage the ship and their food source, the former Navigators awakened a military congent, a few at the time. They mentally enthralled them and enslaved them. Molding them over generations.

As generations passed under the accelerated mutagenesis of the manifold, both the Navigators--calling themselves the Masters now--and their soldier caste had diverged significantly from their original genotype. The Masters had long ago authorized larger scale awakening of more of the colonists to serve as a more docile slave caste--and cattle.

The Masters grew complacent and removed from human concerns and feelings. They didn't see the revolution coming. A soldier named Gith lead a coalition of the soldiers and the menials against their oppressors they now called Mind Flayers after their manner of feeding.

The former Masters were either killed or used their power to flee into the nonspace. The coalition that had brought about their downfall did not long survive. Former menials resented the soldiers as long time collaborators and the soldiers disagreed with the menails attempts to master Mind Flayer psionic disciplines.

When the ship was finally cannibalized and destroyed, two cultures had emerged as firm in their hatred of each other as they were in their former masters.