Magestorm by Jonathan Green

Lord Archaon's dark hordes of Chaos are rampaging across the Old World and all good men of the Empire must heed the call to fight against the encroaching evil. Standing to the fore is fire wizard, Gerhart Brennend - a loner whose mysterious past is drenched in tragedy. As the Storm of Chaos approaches the Imperial city of Wolfenburg, a desperate battle looms and blood will be spilled like never before! Wolfenburg must not fall!