Your curse intermingles with the lost vitality of a cursed enemy to reveal a glimpse of the future to you.

At-Will  
Free Action      Personal

Prerequisite: Star Pact

Trigger: An enemy under your Warlock's Curse is reduced to 0 hit points or fewer

Effect: You gain a +1 bonus to any single d20 roll you make during your next turn (attack roll, saving throw, skill check, or ability check). If you don't use this bonus by the end of your turn, it is lost.
    This bonus is cumulative; if three cursed enemies drop to 0 hit points or fewer before your next turn, you gain a +3 bonus to a d20 roll during your turn.

Published in Player's Handbook, page(s) 131.