Death Throes

As the killing blow falls, you smile with grim satisfaction
even as the light of life fades, knowing that your enemy will
soon be joining you in the afterlife.
You touch a freindly creature enchanting it for the duratio
If the target is killed while this spell is active, it's body is
instantaneously destroyed in an explosion that deals 10d10
points of necrotic damage to everyone in a 30-foot-radius
burst, a contitution save for half.
This explosion destroys the targets body, preventing any
form of raising or resurrection that requires part of the
corpse. A wish, miracle, or true resurrection spell can restore
life.
At higher levels. For each level above 5th, the damage
dealt is increased by 1d10.