Shards of the Shattered Pact: Seowyn's Crossing
No one is sure exactly what the first demons were. Some suggest they were a race of foul entities from the depths of the Elemental Chaos called the tanari’i. Some say that they were Primordials who fled into the depths of the Abyss rather than be imprisoned by the Gods. Whatever they once were, what they are is chaos and destruction incarnate.