Blood-Frenzy is a 13th level encounter power available to Barbarians.[PrP:17]
Blood-Frenzy Strike
Barbarian Attack 13
Your heavy blow draws blood and undermines the enemy's resolve in the face of greater damage.
Melee weapon
Target: one creature
Attack: Strength vs AC
Hit: 3[W] + Strength modifier damage, and the target gains vulnerable 5 to all damage until the end of your next turn.
Thaneborn Triumph: The vulnerability to damage equals 3 + you Charisma modifier.