The Armories of Hell are an area of the Burning Hells dedicated to storing weapons and armor. Structurally, the armories (or at least the area around them) have walls and stairwells made from enormous bones, speculated to be taken from the bodies of giant demons slain in the Sin War. The stairwells in particular appear to be taken from a massive creature's ribcage. All of the walls have a motif that is composed of either jutting bones or rising horns. Deadwood trees spring up from the ground, upon some of which rest the corpses of impaled victims.
The armories of Hell have been seen in the original Diablo, specifically on the first level of Hell. It is here that the player finds weapon/armor racks that can potentially drop very powerful weapons and chest armor. The armories, however, are restricted to singleplayer games, and only if the Warlord of Blood quest is present in those games.