Abidun

In all my time hunting horrors, I have never had any luck tracking down and binding Abidun. Always I would come upon some place he has tread, riding the dreams of the unsuspecting until their heart gives out or madness takes them. Sometimes it is both. The only thing I consistently find in his victims that have succumbed to the madness is this rhyme they speak over and over and over until their tongue gives out just before their heart stops.

Here I am drifting down searching for sleep.
But a gate bars my way, dread Abidun.
Like Leviathan he hides in the deep.
His oily hands grasping me for his fun.
There is no escape. There is no way out.
Beli please rescue me from his fierce jaws.
His moist darkness fills me. Why can't I shout?
Oh mother is that you? Oh no! Oh! CLAWS!

~ From Taubha’s Lesser Book of Names

Of all the members of the House of Ghabegh, there are few so ill documented and understood as Abidun. When he is seen, he appears as an oily darkness with a vaguely humanoid shape, that leaves an oily residue on everything he touches. It is not clear what or who he might have been before the Madness took him, but what is certain is that he delights in tormenting his victims with inescapable nightmares.

When using Abidun in play, he can easily serve as the central antagonist of a mystery, remaining off screen until the time is right, or having him strike and retreat as appropriate. The twists for such and adventure should include normal people turning mad and violent, seeing the adventurers as something to destroy.

Perhaps he haunts the dreams of the denizens of a tower, driving them towards madness one night at a time. The number of people in the tower can then work effectively as a time clock for the adventure, with one or more turning mad and into an enemy each night until there are no more victims and Abidun has won.