Curse of Blood Rot

The caster drives a blade into their gut, releasing their blood sacrifice of 1d20. They coat their hand in the blood of the wound an a Seal of Binding Rot is emblazoned on the caster’s palm. They make an unarmed attack, adding their spell attack bonus, upon successful attack target is marked with the curse of blood rot. The target can only remove the seal with a 9th level remove curse. When the seal is placed on the target, they must make a constitution save equivalent to the caster’s spell save DC + 1d4. Upon a failed save they take an amount of damage equivalent to blood sacrifice damage times ten. Upon a successful save they take half damage.

If the creature remains, it loses an additional 1d12 each round.