Armelt of Sun Tzu

The spirit of Sun Tzu, the greatest tactician that the planes have known of, now follows you in the midst of battle

Every time you land a critical hit, you regain one superiority dice. If you have all your superiority dice available before you land a critical hit, roll a DC 13 Wisdom check. On a success, you add the extra superiority dice. On a fail, you lose all the extra superiority dice that have been added this way.

Extra superiority dices are automatically removed once you finish a long rest 

Notes: Combat