Trial chambers are the combat-loop structure: repeatable fights, keyed vaults, and the only source of the mace. They are copper-and-tuff complexes sitting in the upper cave layers, and they are common enough that most worlds have one within a short walk.
Where they generate
Trial chambers form in the overworld cave layers, generally between the deep dark below and the ordinary caves above. They are built from copper and tuff, so the moment you break into one the material change makes it obvious.
They generate in most biomes, which makes them far easier to find than an ancient city — the constraint is depth, not biome.
Trial spawners and how the fight works
A trial spawner is not a normal spawner. It activates when you approach, emits a fixed wave of mobs scaled to how many players are nearby, then goes on cooldown and can be used again later.
- Clear the wave and the spawner ejects rewards on its own
- Ominous versions — triggered by drinking an ominous bottle — are harder and pay better
- Because they reset, a chamber is a renewable source rather than a one-time raid
Vaults and keys
- Ordinary vaults open with a trial key and hold the standard loot table
- Ominous vaults need an ominous trial key and hold the best rewards, including mace-related drops
- Each vault can only be opened once per player, so a chamber is worth bringing friends to
- Keys do not carry between vault types — an ominous vault will not take a plain key
Finding one from your seed
Chamber placement is deterministic, so a finder will point you at the nearest one and save you a long cave crawl. That also lets you pick a chamber near your base to farm repeatedly rather than the first one you stumble into.
Check the version you are on — trial chambers only exist from the release that introduced them, so an older world will not have any until it generates new chunks.
Find trial chambers in your seed
FAQ
What Y level are trial chambers?
In the overworld cave layers, above the deep dark and below the surface caves. Depth is the constraint rather than biome, so they appear in most biomes.
Do trial spawners run out?
No. They go on cooldown after a wave and can be triggered again, which makes a chamber a renewable loot source.
How do I get the mace?
From ominous vaults in a trial chamber, which need an ominous trial key. Ordinary vaults will not drop it.