This can be resolved by the computer automatically, or you can fight the battle using the tactical combat engine. This puts you on a hexagonal grid with your troops arrayed on one side and the enemy on the other. Units take turns moving based on their speed. Each unit can move and then attack any adjacent units. Each unit can also defend, essentially attack a unit that just attacked it, each turn.
Ranged units can attack any unit on the field, but closer units take more damage.
Your heroes also improve the attack and defense ratings of your troops and can cast magical spells to help your units or hinder the opposition. Tactical combat is quite fun, each battle takes at most a couple of minutes and the winning hero gains experience based upon the values of the units killed. Should all units be killed, the opposing hero is removed from play and his artifacts taken by the winner. You can also choose to surrender or to retreat, both of which are bad, but don't result in the loss of your leader permanently. Enemy Artificial Intelligence One of the sore points from the previous installments of the series was an AI that was easy to fool.