The Vault of Heaven
The Vault of Heaven includes AR tiers 31 to 39. The rules for these tiers are a little different than the ones that apply through tier 30.
Entering the Vault of Heaven
If you finish a season at tier 27 or 28, you will start from tier 31 in the following season, placing you in the Vault of Heaven bracket.
Staying in the Vault of Heaven
If you finish a season at tier 38 or higher, you will start from tier 31 in the following season, maintaining your place in the Vault of Heaven bracket.
Falling from the Vault of Heaven
If you finish a season within tiers 29 to 37 after having started in the Vault of Heaven, you will start from tier 23 in the following season. However, if you reach tier 27 or 28 by the end of that season, you will return to the Vault of Heaven in the next season.
Vault of Heaven Special Rule
When attacking another Aether Keep, you will gain an additional 10 Lift if you defeat all defending units without letting any members of your raiding party be defeated.
About Tiers 29 to 30
Depending on your Lift loss, you may drop from tier 31 in the Vault of Heaven bracket to tier 30 or 29. In those cases, normal Aether Raids scoring rules will apply, and Vault of Heaven rules will no longer be in effect.