Mages are units who use magic to attack. They use anima magic, which is broken into wind, fire, and thunder attacks. They upgrade to sages.
Mages' stats have few consistencies, but they will almost always have a very high resistance in place of defense. This and their magical attack make it prudent to use them to block enemy magic users, and avoid direct combat with physical units. After promotion, Mages may use staffs for healing and other utility abilities. It is much preferable to promote them into sages as sages tend to have great strength, speed and magic skill. When promoted to a sage they can become some of your best units, with high magic, speed, and resistance. If made level 20 before promoting, they will usually be able to kill most units with a fire or thunder.