Characters fight as part of an army in one of two ways. Ordinary characters are fielded as part of other units from the start of the game. They are effectively another trooper in the unit with enhanced characteristics and usually a superior Leadership value.
Independent characters are represented by individual models, which fight as units in their own right. However, as we shall see, one of the most useful abilities of independent characters is to join other units in battle, so that they can move in to bolster the battleline where the fighting is fiercest.