Trial chambers: making spawners ominous and what the vaults actually drop
Ominous vaults hold the Heavy Core, the Mace's key ingredient, but only if you make the chamber ominous first. Here is the sequence, the key economy, and what solo versus co-op changes.
A trial chamber run has two modes, and most of the good loot is behind the second one.
Normal versus ominous
A trial spawner in its default state gives a Trial Key and ordinary rewards. Drink an Ominous Bottle, walk in, and each trial spawner that detects you converts:
- spawners glow blue, spawn mobs in ominous gear (and, for five of the fourteen spawner types, more of them), and drop ominous items on you mid-fight
- they drop Ominous Trial Keys instead
- Ominous Vaults — the blue ones — become openable
The Heavy Core, and therefore the Mace, only comes from ominous vaults. There is no normal-mode path to it — and no vault drops a finished Mace.
The key economy
Keys are per-vault-type and do not convert:
| Key | Opens | Source |
|---|---|---|
| Trial Key | normal vault | normal trial spawner |
| Ominous Trial Key | ominous vault | ominous trial spawner |
A vault can be opened once per player. That is the co-op multiplier: four players with four keys get four separate loot rolls from the same vault. The vault does not deplete for the group.
Solo versus co-op changes the spawner, not the vault
Trial spawners scale their mob count to the number of players who have entered their detection range — and they remember. A spawner that saw four players stays scaled even after three leave, until it resets.
So the practical routine for a solo player is the opposite of the group one: keep other players out of range while clearing, then bring them in for the vaults.
Heavy Core odds
The Heavy Core is a rare drop from ominous vaults specifically: 1 in 10 from the unique roll, which an ominous vault makes three times in four — about 7.5% per vault opened. Expect several chambers rather than several vaults. The Mace then needs:
Heavy Core + Breeze Rod → Maceon a crafting table — the Heavy Core directly above the Breeze Rod.
Where the Bad Omen comes from
You need an Ominous Bottle to start any of this. Two sources:
- Raid captains — kill the banner-wearing pillager, get a bottle of a random level, I to V
- Trial chamber vaults — normal vaults can give a level I–II bottle and ominous vaults a level III–V one, which is circular, but it means a first successful run funds the next
Bad Omen converts to Trial Omen when a trial spawner detects you, so you can drink it anywhere except a village. Drink it in a village by mistake and it converts to Raid Omen instead and starts a raid.
Plan the spawner setup for your player count, and the raid waves by difficulty and Bad Omen level, in the Trial Spawner & Raid Planner.