Mages which specialize in casting spells on the battlefield are called Field Mages. Field Mages generally must think fast and be able to cast a variety of damage inducing attack spells as quickly as possible. They are almost always vulnerable when preparing their spells and therefore must be protected. Sometimes multiple Field Mages work together to achieve devastating results. Other uses of a Field Mage may be to spot enemy trap spells or other mages, or to cast defensive spells in battle. Field Mages are often the first targets in battle making their lives short but exciting.
Apprentice - sometimes sarcastically called a walking target
There are higher ranks but those are usually not deployed in the field.
See Military for more details on rank structure.