Theilaxu: Led by a small council of Tleilaxu Masters - the fanatic, xenophobic Tleilaxu were tolerated because of their useful genetic engineering superiority. Although underestimated and loathed by others, they hoped to someday dominate all.
Ixian: The cyborg, Prince Rhombur of House Vernius, leads the Ixians, masters of manufacturing and technologies only they know how to deploy.
Both the Ixians and the Tleilaxu are integral to the economy of CHOAM and the Imperium. The royal family of Ix had once been one of the wealthiest in the Imperium. Because of a successful invasion of Ix by the Tleilaxu and the Emperor’s Sardaukar, and then, after many years, the liberation of Ix by Ixian and Atreides forces, the Ixians and the Tleilaxu are mortal enemies.
This expansion also introduces new game mechanics to help you gain advantages over your rivals.