The Ash of War, when applied to melee armaments (excluding daggers, thrusting swords, and whips), confers the Heavy affinity and introduces the skill:

"Battle Anthem: Utter a resounding war cry to inspire the spirit and amplify attack potency. During its duration, forceful attacks transform into powerful charging strikes."

These war ashes can be found within the dilapidated abode of the Nimgfu warriors.

To acquire this Ash, it is available for purchase from Bernal, requiring an expenditure of 800 runes.