Weapon Supremacy( Player's Handbook II, p. 85)
[Fighter Bonus Feat, General]
You are a grandmaster in the use of your chosen weapon. When you hold it in your hands, no foe can stand against you.
Weapon Focus (PH) (with selected weapon) , Weapon Specialization (PH) (with selected weapon) , Greater Weapon Focus (PH) (with selected weapon) , Greater Weapon Specialization (PH) (with selected weapon) , Melee Weapon Mastery (PH2) (if selected weapon is melee) , Ranged Weapon Mastery (PH2) (if selected weapon is ranged) , Fighter level 18, Weapon Proficiency with with selected weapon,
When fighting with the weapon that you choose for this feat, you gain a number of additional advantages.
You gain a +4 bonus on all checks made to resist being disarmed.
You can wield your weapon against a foe who grapples you without penalty and without first making a grapple check. In this situation, you can take a standard action or a full attack action as normal.
When you take a full attack action, you can apply a +5 bonus to any single attack after your first strike.
Once per round before making an attack roll, you can instead choose to treat your d20 result as a 10.
You gain a +1 bonus to AC.
You can choose this feat only once, for a single specific kind of weapon. The dedication and focus it requires makes it impossible to gain this feat for more than one weapon.