Vampiric Rend

You channel the essence of death into your weapon and use it to pry loose your enemy's soul, exposing it for your allies to feast upon.  As part of the action used to cast this spell, you must make a melee attack with a weapon against one creature and hit, otherwise the spell fails and the spell slot is wasted. On a hit, the target suffers the attack’s normal effects plus an additional 2d8 necrotic damage, and some of the targets life energy is pried out and exposed.  After your attack and until the end of your next turn, any creature that hits the target with an attack regains hit points equal to 2d4 plus your spellcasting ability modifier.  A creature can only regain hit points in this way once for each casting of this spell.  

Undead and constructs are immune to the effects of this spell. 

At Higher Levels: When you cast this spell using a spell slot of 2nd level or higher, you deal an extra 1d8 necrotic damage for each slot level above 1st, and the number of hit points regained by hitting the target increases by 1d4 for each slot level above 1st.