Can witches be removed from the list of mobs that are killed in the automatic removal? They don't spawn naturally, and allow blood mages a constant source of LP, provided they are named.
But you should have a mob spawner, just get the knife of sacrifice and have your mobs land on a altar. Then kill them and out your sigel in To drain the lp. Boom! You got constant life points
I am long past that point. I have a well of suffering underneath my altar, which used to be filled with auto-spawned, undying witches, but now contains cursed earth instead, which seems to be counterproductive with the larger amount of entities spawning and dying then having their drops left on the ground.
The setup that I've had to replace my old witches with is probably even worse than my original witch one, because now the dying mobs drop things, which are left lying around on the floor of the farm, while still leaving approximately the same amount of mobs in the area.