The Pit Depths
In an area known as The Pit lays waste to a lower level, commonly referred to as "The Depths" in which a player is submerged into hell after passing The Golem.
In these depths contain 2 common magma mobs (the bat and the knight) and two types of wizards who will free you from your damnation.
Loot and Bosses
The Pit Depth mobs (except the boss itself) drop magma brain chunks while the Magma Knight as a minor chance to drop his inferno sword, which is sellable for 32,000 coins or useable with its bass 72 power.
The current end-game boss, The Magma Brain, spawns in the depths. It's location is currently unknown