# Avernus Avernus serves as the front line of the great clash between the evil forces of chaos and law known as the Blood War. Demons from the Abyss use the River Styx to enter Avernus, where they hurl themselves against infernal legions of devils. Avernus was not always the blasted, war-torn battlefield it is today. Long ago, it was a plane of lush gardens and bucolic beauty created by Asmodeus to tempt mortals. The intrusion of the River Styx followed by endless waves of slavering demons destroyed this paradise, leaving layer upon layer of bones, ruins, and shattered war machines. Pieces of cities stolen from other planes, tiny remnants of Avernus’s lost beauty, evidence of destroyed celestial armies, and tombs of ancient travelers all dot the Avernian wasteland. The devils of Avernus seek to exploit pride and wrath, promising the aggrieved, enraged, and egotistical the power to fulfill their darkest obsessions. Such fulfillment, however, comes at a price. Anyone entering Avernus finds a battlefield unlike anywhere else in existence. Evidence of past carnage, such as the ruins of enormous war machines and fields of bleached bones, stretches across the horizon. Through it all, the River Styx winds its way across the plane as knots of demons and devils skirmish along its fetid banks. ### Zariel’s War In some ways, Zariel is a jewel in Asmodeus’s crown—a former angel, now an archdevil, in his infernal service. Despite the conflict within the diabolical ranks, Zariel runs a tight ship and instills fear in her legions. Retribution against those who attempt to betray her is swift and terrible. ### War for Souls Souls are the most prized commodities in the Nine Hells. The Blood War taxes Zariel’s armies, so she must ensure a fresh supply of souls as replacements. To this end, Zariel looks for evildoers in the mortal realms who can deliver more souls to her. Because devils can’t simply walk out of Avernus and step onto the Material Plane, they must rely on minions such as cultists and evil wizards, who can contact them and do their bidding in exchange for wealth and power. A select group of devils and mortal followers who seek to cause strife and destabilize harmonious communities serve as Zariel’s chief corruptors. By funding evil groups, making and distributing weapons, and causing random acts of violence in the name of some enemy to ignite the spark of war, devils swell the capacity for mortals to commit acts of evil, corrupting souls by the thousands and thus ensuring the legions of devils are full of diabolic soldiers for the Blood War. \columnbreak ## Features of Avernus The hellscape of Avernus sits under hideous clouds that obscure the vault of the sky, from which the occasional meteor streaks before crashing into the ground. Ambient light continually swells up from just below the horizon as though lit by nine setting suns, yet no actual celestial bodies fill the sky—no sun, moons, or stars. This constant twilight makes it difficult for the denizens of Avernus to track the passage of time. The atmosphere reeks of brimstone and burning tar, and hot gusts of wind shriek across the hellscape to scour the land below. Sometimes these winds swirl into immense sandstorms, which can strip flesh from bone and plunge everything into darkness. Biting flies, hellwasps, and blood-sucking stirges patrol the air, hunting for any source of blood to feed on. Swarms of them can grow so large that they blacken the sky and deafen the ears with the sound of their wings. On the ground, wandering bands of nupperibos—blind, bloated castaways of the damned—move in the thousands like living lakes of groaning flesh in their agonizing search for food. Bone fields, quicksand, bubbling tar pits, lakes of lava, canyons of wailing souls, and salt flats made from the tears of the damned all await those who wander the hellscape. ### River Styx The River Styx courses through the Lower Planes, frustrating every attempt to map it or predict its course. Getting lost while sailing the Styx isn’t the only danger the river presents. Simply tasting or touching its waters can shatter a creature’s intellect and personality, as well as strip away its memories. Certain fiends are immune to the river’s effects, but most creatures have no defense against it. Unless immune to the river’s effects, a creature that drinks from the Styx or enters the river is targeted by a feeblemind spell (save DC 20). A creature must repeat the saving throw whenever it starts its turn in the river, until it fails the save. A feebleminded creature can drink from the Styx and swim in its waters without suffering any additional deleterious effects. If a creature fails its saving throw and remains under the spell’s effect for 30 consecutive days, the effect becomes permanent (no save) and the creature loses all its memories, becoming a near-mindless shell of its former self. At that point, nothing short of a wish spell or divine intervention can undo the effect. Water taken from the River Styx loses its potency after 24 hours, becoming a harmless, foul-tasting liquid. However, arcanaloths, night hags, and other fell creatures might know rituals that can prolong the water’s potency, at your discretion. \pagebreak ### Commerce When it comes to the souls of mortals, the Nine Hells is always open for business. In Avernus, the business is war, making sure the front lines of the Blood War are continuously replenished with fresh troops, weapons, armor, and war machines. The main drivers behind this infernal commerce are treasure and soul coins. Treasure is only valuable to devils because of its efficacy in tempting and twisting mortals (humans in particular) toward lives of corruption, ultimately leading them to forfeit their souls. Because gold has been used for millennia in the Nine Hells, adventurers can find gold coins from civilizations long lost to history. Silver is harmful to devils. Nevertheless, devils trade silver to those wishing to eliminate rivals in their path. ### Food and Drink Wisdom (Survival) checks to forage in Avernus are made at disadvantage. Water exists, but it tastes foul and is hard to find. Food can likewise be scrounged, but the flora and fauna taste revolting no matter the manner of preparation. Even rations brought to Avernus taste bitter and ashen. ### Rests in Avernus There are no “days” or “nights” in Avernus, but time should still be tracked in hour increments. Thus, the characters can take long and short rests as they do normally. ## Demon Ichor Demon ichor is what remains behind after a demon dies. It’s a reduction of demonic blood, viscera, and bodily fluids with the consistency and odor of bile. Enough demons die in Avernus that their ichor forms pools and small lakes. Although the ichor is harmless on most planes of existence, it can warp creatures on the Lower Planes. Devils and other creatures have found ways to use demon ichor in rituals and to improve the performance of infernal war machines. When a creature comes in direct contact with demon ichor in Avernus, it must make a DC 10 Constitution saving throw. Fiends, oozes, plants, and undead automatically succeed on the saving throw. On a failed save, the creature is magically warped by the ichor, as determined by rolling on the Flesh Warping table. A spell that removes a curse ends all ichor-related warping effects on a creature. ## Soul Coins Soul coins are about 5 inches across and about an inch thick, minted from infernal iron. Each coin weighs one-third of a pound, and is inscribed with Infernal writing and a spell that magically binds a single soul to the coin. \columnbreak A creature carrying the coin can use its action to expend 1 charge from a soul coin and use it to do one of the following: Drain Life. You siphon away some of the soul’s essence and gain 1d10 temporary hit points. Query. You telepathically ask the soul a question and receive a brief telepathic response, which you can understand. The soul knows only what it knew in life, but it must answer you truthfully and to the best of its ability. The answer is no more than a sentence or two and might be cryptic. Hellish Currency. Soul coins are a currency of the Nine Hells and are highly valued by devils. The coins are used among the infernal hierarchy to barter for favors, bribe the unwilling, and reward the faithful for services rendered. Soul coins are created by Mammon and his greater devils on Minauros, the third layer of the Nine Hells, in a vast chamber where the captured souls of evil mortals are bound into the coins. These coins are then distributed throughout the Nine Hells to be used for goods and services, infernal deals, dark bargains, and bribes.