It is something warriors hear everytime on the battlefield.
Battle cries is a set of 30 new exciting facial expressions and the zeroed face that will bring out the fight in all of your renders.
THIS SET OF EXPRESSIONS WILL NOT CHANGE YOUR MORPHS, SO THEY CAN BE USED WITH ANY CUSTOM CHARACTER YOU DESIRE TO RENDER WITH IT. ;)
PLEASE, keep in mind that any morphed character or poses has is own characteristics and so you can have issues with this set. This doesn't depend on our facial expressions but on how the characters and poses are created.