Blade of Mourning

You imbue your weapon with necrotic energy that drains life from your foes. For the duration, your melee weapon attacks deal an extra 1d8 necrotic damage, and you regain hit points equal to half the necrotic damage dealt. If a creature is reduced to 0 hit points by this weapon, it must make a Constitution saving throw or rise as a specter under your control until the spell ends.