With a shout, you direct your ally's blow where it will inflict the most harm.

Encounter   ✦     Martial
Free Action      Close burst 5

Trigger: An ally in the burst attacks an enemy

Hit: The attack scores a critical on a natural roll of 19 or 20. If the target is a dragon, it scores a critical on a natural roll of 18, 19, or 20.

Published in Dragon Magazine 369, page(s) 52.