Essences are what classes of the Fighter archetype use to improve their Combat Arts. All Fighters begin with the Apprentice version for each Combat Art they recieve when leveling. The Journeyman level (Handcrafted tier) can be crafted with common harvests and fuel by PCs by using Alchemy at an Alchemy Table. Adept level (Treasured tier) tomes are drops like other classes upgrades. Expert essences (Mastercrafted tier items) can be crafted by Alchemists using rare loams and other common harvests. Master level (Fabled) tomes are very rare drops in chests from monsters.

Other classes use other item types for ability upgrades; Mage and Priest archetype classes use scrolls made with Scribing, while Scout archetype classes use runes created through Artificing.