The Cleric Quintet: Canticle (The Cleric Quintet #1)

The evil wizard Aballister has spent two years collecting and brewing a potion of power, as told to him by the imp, Druzil, sent by the Goddess of Poison, Talona. When he reveals it to his evil fellowship at the hidden stronghold Castle Trinity, the priest Barjin takes control of it and sets off to the major stronghold of the Snowflake Mountains - the Edificant Library. He finds an innocent, intelligent, and young, low-ranking priest, to open the potion, the Chaos Curse, which makes all who breathe it lose self-control. Cadderly must fight a memory-blocking spell in order to lift the curse and save the Library.