The Coal Pits is the second biome on the main path. It comprises a series of caverns extending through coal veins and rock, with occasional piles of coal and gunpowder and abandoned mining equipment.
The theme that plays within the Coal Pits is Liekkiö.
This biome consists mostly of thick sections of coal veins and rock with wide open passages, with wooden beams blocking off certain areas or providing platforms to stand on. The long tunnels are frequently dead ends which necessitates lots of backtracking to progress further, unless lots of explosives are used. Gold deposits litter the terrain which can be dug out with suitable spells (Chainsaw, Digging Bolt, Energy Orb, etc). Note that coal vein is much easier to dig through than grey rock. Deep pools of water and pools of Toxic Sludge are also abundant. Because the biome has no "safety room" present in later biomes, it is possible for pools of Toxic Sludge to generate directly under the Holy Mountain entrance.
The area is also littered with rigid body minecarts, toxic explosive barrels and loose rocks. It also has toxic sludge tanks hanging from the ceiling, sea mines and platforms supported by chains, often with rocks and explosives on them.
- Biome shops are a rare spawn in this biome. They consist of a short platform with 5 randomly selected spells for sale, similar to the equivalent in Holy Mountains.
- Vats of gunpowder are a very frequent occurrence. Igniting them may provide access to new passages or wands located beneath them through the terrain destruction that ensues.
- Mining machinery can occasionally be spotted, serving no functional purpose but being a fun distraction with their spinning wooden wheels.
- There is a small chance of a strange little cube spawning somewhere in this biome, decorated with runes that can be translated to MEDITATE.
The Coal pits feature several new creatures as well as other types of Hiisi, including:
Leaving the zone via the portals at the bottom will take you to the Snowy Depths.
An area of Fungal Caverns can be found to the west of the Coal Pits, featuring significantly more powerful wands than are found on the level, as well as many flasks, but also significantly deadlier enemies.
A metal capsule-shaped structure will sometimes appear, with a small pool of Water in the bottom. Emblazoned on the inside of the capsule is the alchemical symbol of Water, the downward-pointed triangle, and an image of a cloud is etched into the ceiling of the capsule.