The The Fall of Ythryn Title update for Idle Champions of the Forgotten Realms has 5 achievements.
Gain the final clue to enter the Spire of Iriolarthas and face the Demilich of Ythryn.
Gain the final clue to enter the Spire of Iriolarthas while Iriolarthas chases you.
Destroy the Ythryn Mythalar, using whatever means necessary.
Destroy the Ythryn Mythalar, while the glacier crumbles around you.
Destroy the Ythryn Mythalar, with only one of each class at a time.