The Forgotten Hall involves a number of stages that are rather difficult to complete. Defeat all enemies in each stage of the Forgotten Hall to complete the challenge and claim gratifying rewards. In addition, extra rewards can be obtained by fulfilling specific stage bonus conditions. Equilibrium Levels will not affect the difficulty and rewards in Forgotten Hall stages.
Forgotten Hall contains two types of stages "Memory" and "Memory of Chaos". The former involves stages that will be unlocked gradually as you continue your exploration, while the latter features stages of higher difficulty with content and rewards updated periodically.
You will be cut off from the outside world when entering the Forgotten Hall, with the following actions temporarily disabled:
- Change team setup
- Change, level up or ascend Light Cones and Relics
- Level up or ascend characters
- Use Consumables in your Inventory

Memory Turbulence

The Forgotten Hall features unique rules, with each stage having a different stage effect that adds to the dynamics of combat, making each stage challenging in its own way.

Cycles

All battles taking in the Forgotten Hall must be won within a certain number of cycles. When you run out of cycles, the challenge will fail.
The remaining cycles will be displaying on the action order on the left-hand side as a count-down. Complete the challenge within the designated turns and meet specific stage bonus conditions to obtain extra rewards.