Here is the full list of all 40 Warhammer Age of Sigmar: Tempestfall achievements.
Fall to your demise during climbing
Use dash or teleport three times in quick succession
Tear apart a puny Skeleton
Find a Soul Echo
Witness the destruction of Sigmar's monument
Find a piece of mythical Sigmarite
Find a long-lost weapon spell scroll
Enhance your weapon using the anvil
Unlock all weapon enhancements for the Tempest Blade
Unlock all weapon enhancements for the Stormstave
Unlock all weapon enhancements for the Aetherstave
Fully upgrade your weapons
Perish in battle, and descend upon the battlefield once again
Complete a side mission in the City of Dreadheim
Defeat any Nighthaunt
Defeat a Spirit Torment
Restore the collapsed arch using the Gravesand Hourglass
Obtain the Gravesand Hourglass
Use the Aetherscope and find your destination
Survive the Atheneum lift ride
Seal away the Gravesand Hourglass
Set sail and cross the sea
Obtain a piece of the Penumbral Engine
Meet your warriors in the Shrine to Sigmar in Dreadheim
Find the secret corridor in Prison
Neutralize the Penumbral Engine
Witness the Necromancer's transformation
Free the trapped souls and fulfill your mission
Defeat 50 Skeletons
Defeat 50 Nighthaunts
Defeat 5 Spirit Torments
Collect 10 of Sigmarite pieces in the game
Collect 30 of Sigmarite pieces in the game
Cast 50 spells
Use the Raise spell 20 times
Defeat 50 enemies with the Tempest Blade
Defeat 50 enemies with the Stormstave
Defeat 50 enemies with the Aetherstave
Complete all side missions
Lose your way in the fog