Not everyone in Mordheim had a chance to experience fighting in a big, organized warband, nor did they work on their own as mercenaries. Sometimes groups of fighters, bored with constant lingering in taverns, choose to ally themselves with anyone who was willing to hire them.
The following rules are to alleviate the growing frustration with some warbands’ limits and rooster predictability.
How many times before, told of your opponent’s fraction choice, were you able to quite precisely guess which units will be used against you? How many times using a particular rooster were you in need of units either cheaper, or different in specialization? How many times singular mercenaries did not prove sufficient to fulfill the warband’s needs?