Backstab
You take a split second to locate the most vulnerable point in your enemy’s defenses.
Encounter Martial
Free Action Personal
Trigger: You make an attack roll against an enemy within 5 squares of you using a basic attack with a weapon. The enemy must be granting combat advantage to you.
Effect: You gain a +3 power bonus to the attack roll, and the enemy takes 1d6 extra damage if the attack hits.
Level 7: 2d6 extra damage.
Level 17: 3d6 extra damage.
Level 27: 4d6 extra damage.