You merge them with a Army that already has had some some battle experienece. When this is done the older recruits will train their new colleagues. You can only merge Armys of the same types e.g you may not join a siege weapon with archeres or archers but you may merge infnatry with infantry and...
Sooo many XD's . XD . Making a new creature looks like fun but no one would ever have the time to do soo and as Kays says you need to add it to the game somehow. ( starts thinking of a plan to steal stuff from lionhead)
heh I won The final land by impressiveness . Jut got my creature to stay outside the wall and fight had a platton or two inside my walls and 4 platons of archers on my walls. every so often I would heal my creature, and platoons.