The One in Darkness
A powerful entity that little is known about other than rumor and myth.
Some say that the One is an alias for a dark god such as Vecna or Lolth, other say it is a powerful devil that holds court in the Nine Hells, and some paint it in a better light as a lost god or powerful angel working from the depths of the Underdark.
Regardless of how little is known about the One in the Darkness, every murmur of its name is enough to silence a room and is met with awe and fear across Anduris.
After reuniting with Mortekan, he explained that the One in the Darkness was a god that was destroyed during or in the wake of the Dawn War. While the god was destroyed, and its home plane taken, the domain that the god governed was never taken up by another. The power of the dead god resided in darkness for ages until it grew into a will of its own, calling itself the One in Darkness. According to Mortekan, the One in Darkness seeks revenge for the great injustice it was dealt, and is using Void to accomplish it.