The Ixians were a society that specialized in the production of complex machinery that often flouted the proscriptions of the Butlerian Jihad which led to a taboo on the constructions of machines that bore the exact human mind's image. Its name was derived from the their home planet that was the ninth of Alkalurops.
The Ixians were ruled by House Vernius. Emperor Elrood IX, who desired a Melange substitute and who wanted to pay back Dominic Vernius for two offenses against him. Elrood IX felt that Vernius had stolen a concubine (who later became Shando Vernius) from the Emperor. Vernius had also constructed larger Heighliner ships, stripping Elrood of some tax revenue. Elrood decided that a Tleilaxu invasion of Ix would kill two birds with one stone. ==References and notes==
The Tleilaxu invaded Ix on the (somewhat justified) pretext that House Vernius were creating thinking machines (a fighting Mek was created shortly before in the story). Some years later the Ixians were freed from the Tleilaxu, with the help of House Atreides. ==References and notes==
Even after the liberation of Ix, many within the Imperium felt that the Ixians often strained or broke the universal ban on artificially intelligent machinery. However, astute political dealings, and the hunger for Ixian products, almost always kept the planet one step ahead of an outright invasion by the forces of the Great Houses.
Evolution of the Ixians
By the time of Paul Atreides' emergence the Ixians were, other than the Bene Tleilax, probably the most successful of the fringe worlds that maintained a sophisticated technological base, having had their technological base rebuilt at the cost of House Corrino reparations. They had effectively seen off competition by House Richese in the field of research and development, and their form of government seems to have been transformed into a meritocracy or perhaps Technocracy. Politically they operated as a confederacy, at least in title.
During the Famine Times the Ixians became a major power in the known universe. The Ixians were the first to invent and manufacture no-ships, which contain machines that duplicate the abilities of Guild Navigator, and were able to hide the people within from prescience. These vessels also had the advantage of being far cheaper than traditional space ships. Indeed, it was the development of this cheaper form of space travel which fueled the Scattering.
By the time of the arrival of the Honored Matres, the power of the Ixians was at its apex with their alliance with the Fish Speakers; but Bene Gesserit analysts saw them as a failing power, because Ixian society had become a bureaucracy and no great inventions had come out of the workshops of Ix for centuries.
When the Honored Matres conquer the Old Empire, the Ixians are reduced to being a barely tolerated technological combine.
Ixian Technology in The Dune Games
The Ixians are responsible for providing the technologies for the three Houses to build their unique tanks. This is done by building the Ixian Research Facility at the player's base. Once this is done, the player will be able to build either the Atreides Sonic Tank, the Harkonnen Devastator, or the Ordos Deviator. Other than that, they serve no other purpose.
Emperor: Battle For Dune
In the War of Assassins, the Ixians now play a more direct role in combat, interacting with the three Houses as trading partners. An alliance with House Ix can be forged by aiding them in various missions, providing that the player doesn't ally with the Tlielaxu first, as the two are bitter enemies.
Once allied, the Ixians will provide the player with units built from the House of Ix. These include the Infiltrator (a stealthed mobile kamikaze unit that reveals cloaked enemy units when it detonates), and the Projector Tank (fast hover tank with light mounted cannon, which when deployed, is able to project holographic images of the player's troops that provides realistic damage, yet disintergrates harmlessly on impact).
Behind the Scenes
The authors' sub-plot of Ix being ruled by a Great House (House Vernius) is never mentioned in Frank Herbert's original novels, in which the planet is mentioned exclusively as a technocracy. Thus House Vernius and their rule of Ix should be considered non-canon.