Rune of Battle [Rune]

Epic Tier
Prerequisite: 21st level, runepriest
Benefit: Whenever you score a critical hit with a runepriest power, one ally adjacent to the target can make a melee basic attack against that target as a free action. The ally gains a bonus to the attack roll and the damage roll equal to the number of rune feats you have.

Published in Player's Handbook 3, page(s) 192.