Volume 1: The Mark of Merlin
The Mark of Merlin introduced the Unsorted to the world of Duology, where the mystical Marcana and the logical Illuden exist side by side in a state of constant conflict. Participarts eagar to learn which school of magic they belonged to took part in The Sorting Trials where they discovered that they were a bearer of The Mark of Merlin, one chosen to fully embrace both schools of magic with the potential to forge peace between the long warring factions.
After you're done here, continue reading Prophecy of the Dead to find out what happened next.