Unnerving Calm( Tome of Battle: The Book of Nine Swords, p. 33)
You know that the secret to defeating your enemies lies within the still center of your own mind. When your enemies meet your eyes, they see only calm and certain death awaiting them.
Concentration 1 ranks, one Diamond Mind strike,
Perfect Clarity of Mind and Body (ToB) ,
You can use your Concentration skill instead of your Intimidate skill when you engage in a duel of wills (see page 27). You gain a +4 bonus on skill checks made to resolve a duel of wills. If your enemy chooses to ignore your challenge, you gain a +2 morale bonus on attack rolls against that opponent for 1 round.
Resolving a duel of wills requires an Intimidate check. You gain a +1 morale bonus on attack rolls against an opponent who ignores your challenge.