The Mage is one of the 10 classes avaliable for play. It can be unlocked by killing special enemies, which sometimes will drop trophies. If playing with the Adventurer class, the trophy will have a 100% chance of unlocking any class & race, which may be the Mage or any other class not already unlocked. If playing with another class than the Adventurer, the trophy will have a 50% chance of levelling that class up, and a 50% chance of unlocking a new class & race.
Unlocking the Mage also unlocks the race: Changeling
Class perk: Gifted (5% of healing potions spawn as mana potions. If a skill is undergoing a cooldown period, collecting a mana potion will reduce that cooldown by 1 turn)
Class flaw: Frail (-10 maximum health)
Class skill: Rune (if you trace a closed path this turn, collect all tiles inside it)