Fortune's Favor is a 13th-level encounter power available to Barbarians .[PrP:17]
Fortune's Favor
Barbarian Attack 13
You strike at an odd angle gambling that your enemy will react by maneuvering into the force of the blow.
Melee weapon
Target: one creature
Attack: Strength vs AC.
Hit: 4[W] + Strength modifier damage. You can reroll the attack, if the reroll hits then it deals an extra 1[W] damage. If the reroll misses, then the attack deals 1[W] less damage.