Vampiric Blade

As part of the action used to cast this spell, you must make a melee attack with a weapon against one creature within the spell’s range, otherwise the spell fails. On a hit, the target suffers the attack’s normal effects and your weapon then syphons the life force of the target, the target needs to make a constitution saving throw against you spell save DC, on a failure the creature loses a hit dice and you regain a number of Hit Points equal to your spell casting ability modifier so long as the attack dealt damage. This effect does not apply to constructs and undead.

At 5th level, the attack you make with this spell deals an extra 1d8 necrotic damage to the target. This damage increases by 1d8 at 11th level (2d8), and at 17th level (3d8).