Avernus

"Ah yes, Avernus, very welcoming, in a warm 'just want to rip your head clean off' way" -Letha Everett
  Avernus is the first layer of the Nine Hells of Baator. The most likely beachhead for any attack by demon-kind, it was the primary battleground of the Blood War: legions of devils marched across its plains in continual readiness to repel the hordes of demon invaders that sailed the River Styx into the layer.   Avernus is the largest layer of Baator and one of the most traditionally infernal—a blasted hellscape in the most literal sense filled with rivers of lava, barren hills, and low, rocky mountains as far as the eye could see. To scale the mountains or move too quickly was unwise at best, since obsidian, quartz, and other crystals jutted from the jagged land, cutting clothes and slicing flesh. The ubiquitous presence of rocks and boulders, some of which seemed to resemble tormented faces and shapes of creatures, rendered the terrain extremely treacherous and difficult to cross at any pace quicker than a fast walk. Rubble covered the vast, ashen plains of Avernus's charred wastes.   Blood, as it would happen, was the leitmotif of Avernus; it was where the River of Blood ran through Baator, collecting rivulets from every gulch, stream, and pool, from the victims of millions of battles. Practically all of the plane was bathed in a coat of blood and covered with bones and gore, whether devilish, demonic, or otherwise, acting as a grim reminder of the regular bloodshed that marked an average day in Avernus.  

Government

  Whether for the living or the dead, Avernus was the entry point to Baator and the most commonly visited of the Nine Hells, since Erathon forbade any portals opening to other regions. Because of this, damned souls had to come through Avernus before reaching other layers of the Nine Hells and so the layer was frequently inhabited by the servants of other archdevils, such as the barbazus that gathered the forsaken, or imp and spinagon messengers. The primary reason for the magical restriction was that, for a demonic invasion force to access the lower layers of Hell, they would be forced to conquer and claim the layer directly above it. As the buffer between the Nine Hells and the Abyss, Avernus was incredibly dangerous even without its natural hazards, as baatezu armies trained for future battles. While the layer was once bustling with cities and citadels, centuries of fighting the Blood War ravaged it so that only perpetually rebuilt strongholds and fearsome fortresses remained. It was in a state of constant expansion by military conquest.   The ruler of Avernus was titled the Lord of the First. This position is held by Aradath, She resided in a soaring basalt citadel.
Type
Dimensional, Pocket
Location under
Owner/Ruler
Characters in Location