There's nothing better than letting out a battle cry before charging into your enemies in an RPG. Dragon Age: Inquisition's War Cry affords your warrior some more health to work with in the upcoming battle.
A particularly well known battle cry came from the Ancient Grecian Phalanx. Directly before charging into battle, the Greek warriors would bang their shields and yell, “Alala!” or “Eleleu!” With thousands of hoplites crying out, the sound resembled a flock of birds. This served a dual purpose of sounding pretty terrifying and also invoking Apollo, to lay some sweet buffs on them right before battle.
More likely, they were affecting their own adrenaline and pain tolerance. War cries have been proven to have uncanny effects in both of these areas, but without years of psychological case studies, a hoplite would likely think they were being blessed by Apollo.