Blood Corruption

As long as the caster can see the target, and the target has bled, been pierced, or slashed that round or the previous round and not healed.  The caster can concentrate on the wound, corrupting the blood.  The target takes 1d4 the first round, and an additional d4 round every round after as long as the concentration is maintained.  The creature can make a CON save against the casters spell save DC at the end of its turn every round to end the corruption or can heal itself more than the damage it was previously dealt that round or previous round and end the corruption.

At lvl 6 damage is a d6, at lvl 12 damage is a d8, at level 18, damage is a d10.