Sword of Life Stealing

Weapon (any sword), rare (requires attunement)

When you attack a creature with this magic weapon and roll a 20 on the attack roll, that target takes an extra 10 necrotic damage if it isn't a construct or an undead. You also gain 10 temporary hit points.

Life Thief. When the Pommel is embellished with the gem or phylactery from a true lich, life is drawn to the wielder. The extra necroic damage and temporary hit points gained on a 18 or Higher on the d20