The War for Arnor is a modification for Battle for Middle-Earth 1, which plans to add Arnor faction and adding an Angmar faction in future while revising all other factions.
Horn of Arnor is a 1st Tier Special Power for Arnor Faction, which will give target units P Damage and P Armor for a short period of time. This is it's FX, a re-color of War Chant's FX.