The Abyss is a plane of pure malevolence, from the sludge that oozes from every pore in the ground to the toxic fumes that fill the air. There are near infinite varieties of foulness across the Abyss; some of it reeks of burnt hair, some of it leaves an oily filth over every surface, and some of it clings to the ground like a physical force. Every plant, animal, bird, and beast originates from the foulness here and the pure loathing it incites in travelers cannot be overstated.
As the pure embodiment of true and utter evil, everything on the Abyss is hostile towards living creatures. Some of it is passively hostile, like small plants that lurk in the salt jungles of the Gaping Maw, while the vast majority is simply dangerous. Subtlety is almost unknown on the Abyss, so if something can be dangerous it likely is, but the raw chaos that runs through the infinite layers can create surprising yet still terrible dangers.
Chaos and evil are born and born again an infinite times across the infinite layers of the Abyss. There’s no such thing as good luck here – any bad thing that could go wrong does, and in worse ways than could be imagined. However, it may surprise many to learn that these random acts of terror actually affect all creatures equally, so that rampaging goristro charging across the black dust-choked wasteland may fall into a sudden crevasse. But what lurks in the crevasse is likely worse than the Goristro.
There are infinite layers of the Abyss, and each offers a different perspective on the manifestation of evil. The Random Abyssal Layer generator found later can help create unique horrors for each layer, but there are some constants even in such a chaotic and unstable place.
The first layer of the Abyss is known as the Plain of Infinite Portals. This is a broken, endless landscape of blasted red stone baked under a bloated crimson sun that never sets. Innumerable pits lead into darkness, many offering one-way portals to random layers of the Abyss. The sky in the first layer is ruled by an ancient demon lord named Pazuzu, a remnant of an older order, and he commands hosts of flying demons. His fortress is the Skeleton Tree with twisted bleached branches stretching up to the sky.
The River Styx winds through the Plain of Infinite Portals as well, its brackish waters splitting off into many tributaries through the broken terrain. Some channels lead into pits, sending an endless cascade of Styx water tumbling down across the Abyss.
There are few cities in the Abyss that offer any haven for non-demons, but the succubus sorceress Red Shroud runs the outpost of Broken Reach in the crumbled remnants of an ancient fortress on the first layer as a welcome spot for travelers of all kind. She is a canny creature and always looking for the upper hand, but with the right price mortal travelers can find respite in one of the ruined houses inside Broken Reach.
The Lakes of Molten Iron offer the demonic hordes a source to craft weapons for use in their endless war against the multiverse. Numerous forge-fortresses run by powerful demons squat along the banks of the lakes, but given its importance in the Blood War, infernal legions of the Nine Hells often target the area in planar raids.
The highlights of the Plain of Infinite Portals are not wholly unique in the Abyss, but its position as the first layer and its access to the River Styx makes it better charted and mapped by planar scholars. Further down the layers, details become less reliable. Many are home to powerful demon lords that have taken on aspects of their plane, while others are endless chaotic realms of pure terror and darkness.
But you might be wondering, “How do I get there?”
Perhaps unsurprising considering its many layers, the Abyss boasts more portals and gates across the multiverse than any other plane known. It is thought by some planar scholars that the Abyss forms portals spontaneously at the whim of the demonic horde itself, but if there is some intelligent design behind the portals it has not revealed itself yet.
The top layer, the Plain of Infinite Portals, is the most easily accessed. The River Styx winds through the Lower Planes and connects to the Abyss there, offering easy transportation for those seeking a leisurely journey. Gates are known to exist across the multiverse, in cities and in dark secluded forests, leading to random locations within the Abyss. Some are stable, while others fluctuate, and some can only be opened under certain conditions.
For gates to the Abyss, triggering conditions usually involve some unsavory act or possession – a tongue,
a certain quantity of spilled blood, the flayed hide of a paladin, the heart of a mother, and other such terrible objects. These keys are often documented in unsavory tomes of a dubious nature, though they’re common enough to be found in many Material Plane libraries focusing on planar travel and lore. The Black Cult of Ahm is known to possess a great number of tomes with this level of detail in their secret storehouses across the multiverse.
