The Underworld

The Underworld is the deepest biome in the game, reachable by digging past the stone layer. The Underworld can easily be differentiated from other biomes due to the background wall changing to a lava vein pattern. The Underworld contains partially destroyed buildings called Underworld Houses, which contain Chests, Shadow Chests, Pots and Hellforges. The Underworld is the only biome you will find Hellstone, Ash, Hellforge and Fireblossom.

Monsters
 * Bone Serpent
 * Demon
 * Fire Imp
 * Hellbat
 * Lava Slime
 * Voodoo Demon

Update Info
1.0.4 1.0.5 1.0.6
 * Increased spawn rate of monsters
 * Water now evaporates once it reaches The Underworld.
 * Decreased spawn rate of monsters
 * New monsters added.
 * Underworld Houses can now be made from Obsidian Brick