I am trying to add blood effects to a couple of my spells and am running into problems. Does anyone know how to make it so persists on a target for a spell, similar to what happens when you hit an enemy with an arrow? I have modified the impact data set on the magic effect and can get a blood splash to appear, however none of it "lands" on the enemy and they look squeaky clean once the splash animation is done.

Will bump this just once, surely there must be some way to trigger the blood showing up on the actor.

did you check the Race menu? there are a few checkboxes that control bood splattering.