The Largest Monster

This is a fragmentary idea. Enjoy.

Everyone knows that the greatest monster of all is the Serpent-Tyrant, and the most wicked is man. Few are as clear and quick to answer what the largest is. The Thrip-Sages of Eden, who tap the tree of knowledge for its lifeblood, know that the answer is The Dismal.

On the far west of the so-called Civilized Lands there is a stone road that cuts into a swamp. That swamp seems at first like any other. There is an outpost there, a prison called Westmost. Once it was set on a dry hill looking down on the swamp, now the swamp surrounds it. This is because The Dismal Is Coming.
Travel beyond westmost and the swamp grows deeper, the mud more fetid and sucking. There is a community of Maroon's there, escaped slaves who have built a home atop an ancient pit called Midden Blithe. Beyond Midden Blithe the swamp grows deeper, even more essentiall swampy, and the sky more overcast. A desperate or despairing traveler plunging deeper in The Dismal passes a half dozen communities, and the ruins of dozens more. Strange things live in the swamps and at some point the traveler comes to realize that the sky, once overcast, is now a dark shadow. Looking back they can see vaguely where the sun rises but at some point it passes beyond a great black mass high in the sky. This is because The Dismal is Eating The World.

The Dismal

• The Dismal is larger than anything but the world itself.
• The Dismal wants to eat the world, but it is slow to do it, swallowing up feet by the year as it creeps towards the east.
• The Dismal is a consequence of opening the Gate of Eden. It might stop to rest if the Gates were closed again.
• For thousands of years exiles, runaway slaves and the mad have hid on the edges of the Dismal, leaving many relics behind.