Halo of Warding

Epic Tier
Prerequisite: 21st level, avenger, oath of enmity power
Benefit: While you are adjacent to your oath of enmity target, you can make an opportunity attack against any other enemy that moves into a square adjacent to you, provided the enemy does not shift or is not moved into that square by teleportation or forced movement.

Published in Dragon Magazine 382, page(s) 41.