The mark of your weapon on your target's hide gives strength to your allies' attacks against the same foe.

Encounter   ✦     Arcane, Weapon
Standard Action      Melee weapon

Target: One creature

Attack: Charisma vs. Reflex

Hit: 1[W] + Charisma modifier damage, and each ally within 5 squares of you gains a +2 bonus to damage rolls against the target until the end of your next turn.

  Virtue of Cunning: The bonus to damage rolls equals 1 + your Intelligence modifier.

Published in Player's Handbook 2, page(s) 70.