You are a grandmaster in the use of your chosen weapon. When you hold it in your hands, no foe can stand against you.
Prerequisites: Proficiency, Weapon Focus, Greater Weapon Focus, Weapon Specialization, and Greater Weapon Specialization with selected weapon; Melee Weapon Mastery with damage type of selected weapon; fighter level 18th.
Benefit: When fighting with the melee 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.
Special: 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.
A fighter can select Weapon Supremacy as one of his fighter bonus feats.
Source: Player’s Handbook II, page 85. Changed Weapon Mastery to Melee Weapon Mastery under Prerequisties to match the feat’s listing on Table 3-1 on page 73.