Blood drain

You draw the blood out of up to 3 creatures in range, alive or dead, and absorb it into your hands. Heat yourself for 1d6+1, and add +1 for every source of blood above one. If a target is alive, it takes 2 undefined damage, and if it is brought below 10 hp, it must make a dc 15 constitution saving throw or be knocked prone. If it kills a creature, it is instead knocked unconscious and stays at 1 hp.