The Record of the North
Scholars disagree as to whether the Lords Below are forgotten gods or elder beings of some other sort. What is certain is that they reside in the Duat and wait to invade and conquer this world. They created and are served by vast hierarchies of infernal beings, and of old swore terrible oaths with a few humans, creating the first tieflings. The number of the Lords Below is uncounted, but what is certain is that they never seem to all act in concert, even though small groups of them often support each other. During the Time of Invasions, armies serving this or that alliance of some of the Lords Below warred with each other as zealously as with armies of eladrin, humans, elves, and dwarves.