From Unofficial Ansalon Wiki
A Battlemage is one of the few spellcasters who disregard the more scholarly pursuits of the arcane and instead devotes him or herself to the purely combative aspects of magic. Often, BattleMages are employed by large armies not only to throw nasty spells at the opponents, but to enhance the abilities of their own troops.
BattleMages begin with dagger, just as normal Mages do, but they have the option of learning other weapons, as well as some combat skills.
Battlemages have a more limited spell selection than Mages but still have a large amount of combat spells.