I'm currently running a D20Modern Shadow Chasers game where the Shadow is the byproduct of Bastions (a partially divine 3rd race [where men and angels are the first two]) being sealed away in a cluster of dimensions very near to the prime dimension (ours).
Over time the corrupted species began to polarize - with those who resented the power sealing them away becoming more and more corrupt, and those who saw the light easing out of their corruption. The dimension with the largest number of the darker ones became a very grim universe, filled with the Bastions' own twisted creations spawned of contempt and jealousy.
No one understands exactly how, but at some point in time the dimension transformed from a stagnant realm to a vile and chaotic storm. This chaos consumed all that once lived in that dimension, twisting and carrying it along the winds of this new massive entity - the Shadow. For a time, it stayed within its boundries; it simply churned about as if in a restless sleep... or contemplating its next assault. Years, if not decades later the Shadow became hungry once more and began to spill itself over into the next-nearest dimension. It would do this until its prey fell and ultimately became part of it.
So it would happen until the very last of the Bastions fell battling their fallen brothers and sisters over the final prison dimension.
Now the shadow is hungry again, and it turns to the Prime dimension, meal of meals, for its next course.
Okay, now that I've introduced the background of the game in a nutshell, I can ask my question!
My players have yet to be informed of the existence of Bastions (or angels for that matter) and I'm wanting to introduce a "small" god, preferably from a dead/dying religion, as a corrupted Bastion spewed into the world by the Shadow. I'd like him/her to be someone recognizable, but not too powerful. It needs to be someone "small" enough to be killed/purified by the players.
My players are roughly EL9, and will probably be EL10/11 when they fight this thing.
Thanks in advance for the ideas!
(Also, let's please refrain from turning this into any sort of theological debate. Thanks again.)