(2) Set: When you generate a combo point from Revealing Strike's effect, Honor Among Thieves, or Seal Fate, your next combo point generating ability has its energy cost reduced by 15. Stacks up to 5 times.
(4) Set: Killing Spree deals 10% more damage every time it strikes a target. Abilities against a target with Vendetta on it increase your mastery by 38 for 5 sec, stacking up to 20 times. Every time you Backstab, you have a 4% chance to replace your Backstab with Ambush that can be used regardless of Stealth.