Vampire's Kiss

(Requires attunement by a vampire)
This +1 magic greatsword is enchanted with vampiric blood magic, drawing the blood out of wounds it creates and restoring vitality to its wielder. On a successful attack, the target makes a DC 18 Constitution saving throw. The target takes an additional 2d8 necrotic damage from the attack on a failed save, or half as much damage on a successful save. The wielder regains hit points equal to the necrotic damage dealt in this way.
If wielded by an unattuned creature, the necrotic damage feature of this weapon does not activate and no hit points can be regained in this way.