Avernus

The terrain of Avernus is bleak and hostile—barren plains of cracked, scorched stone, scorched black hills, and jagged mountains under a sky of perpetual crimson haze. Thunder rumbles with no storm, and the air is thick with the stench of brimstone, blood, and burnt iron. The land is crisscrossed by rivers of burning ichor or bubbling blood, which are as likely to carry infernal war machines as they are the mangled corpses of devils and demons.

Rains of acid, blazing cinders, or flaming ash fall at random, and clouds of biting flies and other infernal pests make life a torment even without direct confrontation. Gravity, while stable, seems heavy and oppressive—every step here feels like it’s taken under the weight of sin.

• Legions of devils march and patrol, enforcing infernal discipline and repelling demonic assaults.
• Soul coins—the currency forged from mortal essences—are traded among infernal mercenaries, warlords, and traders.
• Infernal war machines, huge metal constructs powered by damned souls, thunder across the wastes.
• Lost mortal souls and adventurers sometimes band together into ragtag survival groups—or are swiftly claimed by predators.
• Pit traps, cursed ruins, and twisted oases lure the desperate into doom.

Avernus is the front line of the Blood War, an unending conflict between devils and demons. Massive fortresses, siege camps, and infernal war machines litter the landscape. Explosions in the distance, the scream of tortured souls, and the ever-present clamor of battle are commonplace. Warlords of devils command squadrons of lesser fiends and enslaved mortals alike, while wandering demonic incursions erupt in chaos.

Avernus is unique among the Hells in that planar portals open here, but none lead directly to the deeper layers. All must pass through this gauntlet—willing or not. Some portals are fixed (often heavily defended or booby-trapped), while others are mobile or conditional, such as those that open only when certain infernal pacts are fulfilled.