Circle of Blood Rage is a daily power available to the Barbarian class at level 25.[PrP:22]
Circle of Blood Rage
Barbarian Attack 25
Close burst 1
Target: each creature in burst
Attack: Strength vs AC
Hit: 4[W] + Strength modifier damage.
Miss: half damage.
Effect: You enter the rage of the circle of blood. Until the rage ends, you gain a power bonus to attack rolls with barbarian at-will powers and Rage Strike equal to the number of creatures you targeted with this power.