INNATE: Whenever Ahri hits an enemy with one of her abilities, she gains a stack of Essence Theft, and can gain up to 3 stacks per ability cast.
Upon reaching 9 stacks, Ahri's next ability heals her for 3 / 5 / 9 / 18 (based on level) (+ 9% AP) for each enemy hit and consumes the stacks if at least one enemy is hit.