Hex

At-will, swift, ranged; you curse one enemy within range for 3 rounds, or until you hex a different creature. Choose one ability score when you place the curse: the subject has disadvantage on saving throws using that ability, and on skill checks using it. Whenever you damage the hexed creature with a Sneak Attack, it also takes light necrotic damage.

If the hexed creature is reduced to 0 hit points, you gain a soul shard (see Hex).

At rank 2, the hex lasts until the end of the encounter. At rank 3, you can maintain hexes on two creatures at once.