Its an oskill (Comes from certain items).
It can roll on barbarian swords and it appears on
Voice of Arreat
Voice of Arreat
Horned Helm (Sacred)
Defense: 6435 to 7705
(Barbarian Only)
Required Level: 100
Required Strength: 500
Item Level: 120
+(25 to 40)% to Physical/Magic Spell Damage
+(15 to 20) to War Cry
+200% Enhanced Defense
+(3000 to 4000) Defense
Maximum Mana +15%
Maximum Elemental Resists +1%
Socketed (4)
and
Relic (War Cry)
Relic
(Random class Only)
Required Level: 75
+1 to Barbarian Skill Levels
+(9 to 21) to War Cry
+(21 to 40) to Energy