The Relic Altar is unlocked in Act 2 after completing the quest In Search of the Sanctum.
Each character has its own Relic Altar and uses separate Relics. However, the Relic Locker is shared between all of your characters in the same league.
Relics placed in the Relic Altar are locked in for the entire Sanctum run and cannot be added or removed in the middle of a run. The current run must be completed, failed, or forfeited to add or remove Relics.
The Relic Altar contains 20 inventory spaces, but 12 are initially locked.
Unlocking
Locked inventory spaces for the Relic Altar can be unlocked by completing various rooms or floors in the Forbidden Sanctum.
PosX
PosY
Unlock
0
0
Complete the Sanctum Bellum room in the Sanctum Cathedral
1
0
Complete the Sanctum Archives
2
0
Complete the Sanctum Archives
3
0
Complete the Sanctum Vaults
0
1
Complete the Sanctum Vaults
4
1
Complete the Sanctum Cathedral
0
2
Complete the Sanctum Cathedral
4
2
Complete the Sanctum Necropolis
1
3
Complete the Sanctum Necropolis
2
3
Complete the Scriptorium room in the Sanctum Archives
3
3
Complete the Reliquary room in the Sanctum Vaults
4
3
Complete the Mausoleum room in the Sanctum Necropolis
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