Gloom Razor

 
Prerequisite(s): Shadow Blade, Hide 9+ ranks, two Shadow Hand maneuvers.
 
Benefit: The Gloom Razor feat enables the use of three tactical options.
 
Lingering Gloom: To use this option, your opponent must miss you due to concealment. On your next turn, you can make a Hide check opposed by your foe's Spot check as a swift action. If this check succeeds, you gain the benefit of an invisibility spell against that foe until the end of your turn.
 
Moving Shadows: To use this option, you must deal damage to an enemy with a melee attack and move at least 10 feet during your turn. On your next turn, you can treat that enemy as flat-footed against the first melee attack you make in that round.
 
Shadow Slip: To use this option, you must make a successful melee attack against an opponent you flank. On your next turn, you can make a DC 20 Tumble check if you are adjacent to your foe. If this check succeeds, as a free action you can move to any square adjacent to your opponent without provoking attacks of opportunity from any opponent.
 
Source: Tome of Battle: The Book of Nine Swords