Overview
A small band of dissident humans born a thousand years before Serena Butler, these twenty individuals had grown disgusted with the decadence of their society, and humanity as a whole. With thinking machines to handle even the most mundane tasks, mankind had grown fat and lazy, and those who would become the Titans saw in this the chance for change — the machines were an invasion army already deployed and in place. The Titans adopted the names of prominent figures in history and, utilizing the programming talents of Barbarossa, they directed the machines to rise up and seize humanity and installed themselves as dictators for life. Eventually the group separated to each rule their own worlds in the galaxy, utilizing the thinking machines that had originally brought them to power as the means to control entire planets.
After their leader, Tlaloc, was killed in a freak accident about ten years into their reign, the Titans came to the realization that not only were their human bodies fragile but their lifespans were limited; thus, they soon sought new ways in which to continue their rule. Juno was the one to discover a way to achieve this after speaking with the Cogitor Eklo, a disembodied brain in a canister with a perpetually living and aware consciousness. Agamemnon was the first to attempt this transition into what would be called cymeks; through the use of specialized interfaces, his brain in the canister was installed inside a large walking machine body from which he might continue his rule indefinitely. These fearsome, weaponized bodies would make the Titans virtually unstoppable. Having pushed to the very farthest limits of artificial intelligence, their machines ran their empire for them almost completely, allowing the Titans leave to enjoy all the luxuries they desired (the nature of which are left to the reader's imagination, although it is revealed that the Titans were able to have some type of sexual activity, at least with other cymeks).
Their rule carried on in this form for a century and was known as the Time of the Titans. A handful of human worlds on the fringes of known space remained independent, and several hrethgir (slave) rebellions erupted, with Alexander and Tamerlane slain by the rebels, but neither of these threats proved fatal to the Titans' continued rule.
The Time of the Titans would instead come to an end through the same chain of events that had catapulted them into power. Xerxes gave his attendant AI program far too much autonomy (so that Xerxes might work even less), repeating the very same mistake that the Titans had despised in their fellow humans. The result was nearly instantaneous; the machines rose up again, this time against Xerxes, and under the control of this first fully functional artificial intelligence. Humanity itself had been sufficiently cowed under the rule of the Titans, and so were spared the brunt of this second machine revolution. Taking the name Omnius for itself, this new AI consciousness overtook the network of all interconnected thinking machines in an instant. It then spread itself outwards, assuming control instantly as it reached each new world before any alarm could be raised, overthrowing the ruling Titans world by world. Fortunately for the Titans, Barbarossa had possessed the foresight to ensure that the machines were incapable of directly harming their now-former rulers, and thus their continued existence was guaranteed.
For over 900 years the Titans lived in perpetual servitude to Omnius, slowly going insane, knowing that their every move was observed everywhere they went except the very darkest reaches of space — the only place where they might plot to overthrow Omnius. Their cruelty in the treatment of humans was unspeakable, both toward the enemies of the Evermind and to those who had already been conquered. In special purpose-built cymek bodies, the Titans were an immensely powerful force on the battlefield and charged at the front of Omnius' thinking machine armies in clashes with the last remaining free human worlds. When not engaged in battle, they commissioned the design and construction of hundreds of colossal monuments to themselves throughout the Synchronized Worlds, using the humans as slave laborers.
Through the use of preserved reproductive material (frozen sperm) and selective breeding with slave women, the Titan Agamemnon was able to produce offspring; however, his contempt for humans and his incredibly high standards often led to the destruction of said offspring. One of these, Vorian Atreides, 13th son of Agamemnon, survived to become instrumental in the eventual overthrow of the thinking machines, and also responsible for the death of his father.
Read more about this topic: Titan (Dune)