The titans were the first of the three groups of immortal beings spawned (or perhaps created) by the mysterious Elders. The titans played a relatively limited role in the history of the Earth compared to the Elders' other progeny, the Aedra (gods) and Daedra Lords, but the interactions between these three groups of beings set the stage for all of the religious conflict that would follow.
The nine Elders spawned nine titans, just as they later spawned the nine original Aedra and the nine original Daedra. Little is known about why the Elders decided to make each of these groups the way that they did, but two things are known for certain about the titans that distinguish them from their younger siblings: they had no concept of gender, and they were substantially more powerful than the Aedra and Daedra who followed them.
The titans were the first of the Elders' children to discover Earth and its population of mortals. These beings were mere curiosities to them at first, but the concept of sexual reproduction apparently intrigued the Elders enough that they incorporated it into their next two batches of children, the Aedra and Daedra. While each of these new children were weaker than the titans, the females among them did have the ability to birth children of their own, thus propagating their species. (There is no evidence that the titans ever found a means of procreation, even though the Elders themselves obviously succeeded in doing so.)
Alliance and Betrayal
Admin Note: All that we know about the struggle between the titans and the Pantheon comes from the little that the Aedra and Daedra themselves have said about the matter. It is possible that this is neither a complete nor an entirely accurate account of the events surrounding the titans' imprisonment, but we will never know for certain.
The titans, Aedra and Daedra all worked together at first to explore the world of mortals, but it was Ba'al who first discovered that mortals could be used as a "power source" for them to feed on. Up until that time the Elders' children had been limited to drawing on naturally-occurring elemental forces as the source of their power; the sun, for instance, was a potent source of elemental fire. Ba'al discovered how to extract the energy released by a soul's passage into the afterlife, and he proposed the construction of the Nine Hells in order to collect this energy on a global scale. Shortly after that, one of the gods or daedra — some say it was Suspira, while others insist that it was Artela and Lilith working together — discovered that mortal behavior could be drawn on as a source of energy, as well.
These discoveries changed everything; the mortal races, once mere curiosities, were now the most potent energy source on Earth. The questions of how best to use these resources, and who would control them, quickly became a major source of contention between the Elders' children. Though all 27 of them worked together to construct the Nine Hells, the titans asserted that they would be in charge of running these soul-collectors, and their presumption angered their younger brothers and sisters who had first come up with the idea.
At some point during the construction of the Nine Hells, Ba'al approached Kammoloth and proposed an alliance against the titans. If they struck first and took the titans by surprise, Ba'al believed that they could destroy the titans before the Nine Hells made them so powerful that their dominance could not be opposed. The Aedra and Daedra had taken the lead in setting themselves up as gods over the mortal races, and the energy they had collected through mortal worship made them strong enough that victory over the titans was possible. Kammoloth agreed to the plan but insisted that the titans must be imprisoned, not killed; he was afraid that the Elders would return and punish them if they stooped to killing their own siblings.
The details of the war that followed have been lost, but by the time it ended the titans had all been imprisoned in various remote and desolate places: the Great Northern Desert, the moon, deep underground, in the depths of the sea, and in the Wastelands of Kilyarnie (a barren expanse in the middle of the newly-constructed Fifth Hell).
The Elders return
As it turned out, Kammoloth was overly optimistic about the Elders' reaction. When they eventually returned to Earth to check on their children, they were furious at what Ba'al and Kammoloth had done to the titans. Unfortunately, the titans had been driven insane by their confinement, so they could not be released into the world again; the Elders were forced to leave their oldest children bound for eternity. In punishment, and to keep their children from turning on each other again, the Elders bound the Aedra and Daedra to specific spheres of influence in keeping with their personalities and interests. No longer would the members of the pantheon compete with each other directly over the same energy sources, nor could they steal energy from one another — though Kammoloth, Samekkh and Dokorath have been working in secret to find a way around that geas.
The Nine Titans
History has preserved the names of the nine titans and a few details about what they were known for, though in most cases this information is very sparse.
Malekis: Firstborn of the titans, and the most powerful. Sibling to Kammoloth and Ba'al.
Mephisto: Associated with strength, authority, and the will to exercise power. Sibling to Dokorath and Revonos. Mephisto crafted a powerful magical artifact, the Gauntlet of Mephisto, which still exists today; it resembles a clawed, jeweled steel glove that bonds to its wearer and gives him or her tremendous martial power at the expense of an increasing thirst for conflict and battle. As of 706 CR the Gauntlet is in storage in the Lightbringer Vault at Metamor Keep.
Nathales: Associated with the earth (especially caves and other places underground), mining, craftsmanship, and the rewards of diligent labor. Sibling to Dvalin and Agemnos. Nathales discovered mithril and revealed its existence to the Elves and Dragons, teaching them how to mine it and shape it into powerful magic weapons. Nathales' grand projects caused substantial hardship for the mortal races, especially the fragile Elves, but they also resulted in the mining of large quantities of mithril that later proved essential for crafting weapons against the Great Darkness. Nathales is imprisoned somewhere deep underground, probably beneath the Great Barrier Range.
Fallos: Sibling to Samekkh and Klepnos. Little is known about his/her ethos or philosophy.
Lykos: Sibling to Artela and Lilith. Some believe that s/he created the lycanthrope races, hence the name; however, little information about Lykos survives. S/he is believed to be imprisoned somewhere in the Great Northern Desert, though the exact location is hidden from any form of scrying magic.
Each of the eight other planets in the solar system (besides Earth) is named for one of the titans, as is Earth's moon. In order of increasing distance from the Sun, the planets are named Fallos, Amara, Earth, Mephisto, Malekis, Nathales, Salestra, Lykos, and Reshina. Earth's moon, of course, is named for Celine, though it is usually just called "the moon" in common conversation.