What is the Swamp of Oblivion?

The Swamp of Oblivion, also called the Para-Elemental Plane of Ooze, is the elemental plane that lies between the Plane of Water and the Plane of Earth. The mixture of elements from these two planes creates a disgusting realm of slime and mud. 

The Swamp of Oblivion is not a particularly hospitable plane. Few settlements of intelligent beings manage to take hold, and even those that do eventually sink into the swamp. Since there is no solid ground beneath the swamp, everything eventually sinks into the muck. Objects thrown into the swamp are said to disappear for at least a hundred years, making the plane an ideal dumping ground for waste or powerful artifacts that someone desires to be unobtainable for a time. 

The region that borders the Plane of Earth is known as the Mud Hills, while the area that borders the Plane of Water is called the Silt Flats.

Inhabitants

Beasts and other animals are rare in the Plane of Ooze, although there is no shortage of leeches or mosquitoes. Any creatures that can be found in a swamp on the Prime Material Plane can also be found here, although typically they remain relatively isolated and in small numbers. A few humanoid settlements exist scattered throughout the Swamp of Oblivion, populated by people who accidentally stumbled through a portal or were banished here for their crimes.

Outside of the elementals, hags are the primary power brokers in the Swamp of Oblivion. Some hags have uncovered portals to the Plane of Ooze from the Material Plane. These hags may maintain their residence within the Swamp of Oblivion, while safely manipulating events on the other side of the portal. 

Of course, the primary inhabitants of the plane are sentient oozes of all varieties. Gray oozes, ochre jellies, and black puddings can be found in large numbers here, along with their less common cousins. The most powerful oozes are the para-elementals. These para-elementals are somewhat of a hybrid of the water and earth elementals commonly found on their respective planes. Their statblocks are below. 

Para-Elementals

The most common elementals in the Swamp of Oblivion, Ooze para-elementals are dangerous beings made of acrid sludge. While submerged in the swamp, they are virtually indistinguishable from the surrounding water. While not particularly intelligent, they recognize beings not native to the swamp and may become hostile towards them. When summoned to the Material Plane, it is often by hags or other beings native to swampy areas, such as a bullywag or lizardfolk shaman.

Para-Elemental Myrmidons

Like all elemental myrmidons, these creatures are created by powerful summoners who summon and bind the creature to a suit of armor. Most ooze para-elemental myrmidons are created by hags as guardians or to serve as the hag’s representative to lead a war party. While most commonly found on the Material Plane, those who manage to return to their native realm often gather large tribes of ooze para-elementals and serve as their leader. These tribes harass the few settlements that exist in the Plane of Ooze and launch incursions into neighboring planes, attempting to expand the swamp’s territory.

Elder Elemental

The elder elementals of the Swamp of Oblivion are the assimilation oozes. An assimilation ooze is believed to be an ooze that has consumed enough matter to evolve into an extremely powerful and dangerous version of itself that is able to absorb the traits of creatures it consumes. Because of this, assimilation oozes can vary quite widely in their power level and abilities, though often their abilities will come from creatures native to swampy regions. The one shown below has assimilated the scales and natural defenses of a young black dragon, the regeneration ability of a troll, and some limited spellcasting from a slain hag.

Thanks for reading!

Next week: The Fountains of Creation, otherwise known as the Para-Elemental Plane of Magma.