The Elders are nine semi-mythical beings of almost incomprehensible power and a wholly alien mindset. They are said to have created, or given birth to, the three groups of Outsiders that have influenced Earth and its history: the Titans, the Aedra, and the Daedra.
No one knows why the Elders first visited Earth, though curiosity probably had a lot to do with it — humans and other mortals, after all, are a very different form of life from these energy-based beings, and it seems likely that they took a purely academic interest in the carbon-based creatures they found here. The Elders soon departed for other worlds, even other dimensions, but their children stayed; unlike the Elders themselves, who had evolved beyond such concerns, the Outsiders still needed "food" in order to sustain themselves in their energy-based forms. (It has been speculated that the titans, gods and daedra represent a sort of larval form, and that the Elders are the adults of the same species. It is impossible to determine if this is true, though; if there was ever a way for the gods to ascend and become what the Elders are, their progenitors never told them how.) These beings soon discovered that the worship of mortals and the natural forces of a living, breathing world represented powerful energy sources that they could draw on to sustain themselves and reproduce more of their kind.
The Elders have seldom returned to Earth since that early age, and only once have all nine appeared together. They returned to punish the aedra and daedra, who had betrayed the titans by killing or imprisoning all nine of them. The surviving titans had gone irretrievably mad in their captivity, so the Elders could not release them again, but they refused to simply ignore what their younger children had done. In order to prevent future infighting, the Elders bound them to separate spheres of influence, limiting each of them to gathering divine energy in certain specific ways. They could no longer steal power from each other, and a powerful geas prevented them from killing one another (though the gods' and daedra lords' own children are able to slay one another easily enough). The changes the Elders had wrought in their children prevented them from ever leaving Earth and its star system. Having thus put their children on a secure leash, they disappeared.
Since that time only a few people have seen what were believed, in retrospect, to be Elders. Most of these people have gone mad — their utterly alien appearance and the overwhelming power of their minds is too much for the average mortal to withstand. Those who survived with sanity intact refuse to talk about what they have seen in any but the vaguest terms. These sightings have tended to occur at times when one of the titans was in danger of being released; their prisons still exist, both in the Fifth Hell and in remote and desolate parts of the material plane, and power-hungry humans have sometimes opened these ancient vaults without knowing what they held. Rickkter was reportedly part of one such ill-fated expedition; the insane titan destroyed most of his allies before a joint force of gods, daedra, and one of the Elders arrived to help put the outsider back in its prison.
The Aedra and Daedra tend to view the Elders in the same way that humans have viewed their gods: with a mixture of terror and wonder. They rarely pray to them — the Elders have long demonstrated that they care little for this world now that they have left it — but they sometimes invoke them in their conversation, particularly when speaking to each other.