Rage of the War Bringer is a daily power available to Barbarians at level 15.[PrP:18]
Rage of the War Bringer
Barbarian Attack 15
Your strike rings out, and your wrath boils over. You inspire your allies to strike true.
Melee weapon
Target: one creature
Attack: Strength vs AC
Hit: 4[W] + Strength modifier damage.
Miss: Half damage.
Effect: You enter the rage of the war bringer. Until the rage ends, any ally who has line of sight to you gains a bonus to melee damage rolls equal to your charisma modifier.