Large monsters may fight on their own as independent and powerful elements of the army. Some monsters develop loyalty and devotion to their masters and will fight for them willingly, while others may be placed under enchantments or simply driven forward towards the enemy in the hope that they will attack the right targets.
Large monsters fight as single models in the same way as heroes and wizards. Like heroes they do not have to manoeuvre to turn about, and so suffer no movement penalties for changing direction.
The biggest disadvantage of monsters is that they tend to have very low leadership values. This means they can be driven away or panicked very easily. They can also be picked out as targets because they are so big, and a +1 is added to a shooter's dice roll as they are more easy to hit.