Cataclysmic Illness

You imbue every non sentient creature on your current plane with a horrible plague. The plague can infect sentient creatures through the air and bites. When a creature is infected, it begins to develop black boils on its skin and will take one point of exhaustion immediately. Whenever an infected creature attempts to take an action it must succeed a DC 16 constitution save or take 1D6 necrotic damage and its maximum health drops by half of the damage. An infected creature takes 1 point of exhaustion every 5 days. To cure any infected creature must drink any amount of blood from the creature who casted the spell.