Viola's Blood Mote

You can place a mark a creature with a vampiric brand that allows you to siphon its blood upon death. Until the spell ends, you can deal an additional 1d6 necrotic damage to the target whenever you hit it with an attack. When that creature is reduced to 0 hit points, you can regain one expended hit die. 

A Remove Curse cast on the target ends this spell early.

At Higher Levels When you cast this spell using a spell slot of 3rd or 4th level, you can regain two expended hit die. When you use a spell slot of 5th or 6th level or higher, you can regain three expend hit die. At 7th level or higher, you can regain 4 expended hit die. At 9th level, you can use this feature without maintaining concentration and regain 5 expended hit die.