How I Stopped Worrying and Learned to Love Eberron
When the god Aureon was young and still collecting all the magics of the universe, he began to see a dichtomy form in his research. One the one hand, there were the good magics, used to defend the weak, spread knowledge, and help life flourish. On the other, there were the evil magics, used to subjugate, hide secrets, and snuff out life. Aureon realized that he could not simply erase the evil magics, because the balance between evil and good ensured no power grew too great in the universe. But he knew that he favored good magic, and could not be trusted with the evil magics. So, either consciously or unconsciously, Aureon started to siphon off all the evil magics into a separate entity. Slowly, this became the Shadow.
The Shadow imbodies all the reckless ambitions of magic. To control life, information, and free will are all the goals of the Shadow’s worshippers. His holy symbol is a black tower, carved from obsidian when available.