Void's Wrath

Sacrifice your own vitality to bring down the wrath of the heavens. The energies of the void are hard to control and take their toll on the user. Spend 5hp to perform an attack at disadvantage that deals 2d6 points of Necrotic damage. 

At Higher Levels. Use a spell slot higher than second (max lv7) to sacrifice another 5hp/lv to gain an extra 2d6/lv.