The invigorating power of a good war cry should never be underestimated, and Orcs have the best war cry of them all.
Source: Warhammer: The Old World Online Rules Index
Waaagh!URL Copied!
Once per game, during the Command sub-phase of their turn, this character may attempt to invoke the power of the Waaagh! by making a Leadership test (using their own Leadership). If this test is passed, until your next Start of Turn sub-phase this character, their mount and any Orc unit they have joined may re-roll any rolls To Hit of a natural 1 and, when calculating its combat result, may claim an additional bonus of +1 combat result point.
Note that, for the purposes of this rule, an Orc unit is considered to be any unit that is made up entirely of Orcs or Black Orcs, mounted or otherwise. Should an Orc unit be joined by a Goblin character, it is no longer considered to be an Orc unit. This special rule is not cumulative.