If I have Bloodlord of Asgoth in play and I cast a vampire that already has bloodthirst. Does the Bloodlord's bloodthirst stack with the creature's existing bloodthirst or does the creature just get bloodthirst 3 from the Bloodlord?
Comp Rule 702.52c says that if a creature has multiple instances of bloodthrist, they each apply separately. So, your creature would get counters from the {Bloodlord of Asgoth} and it's own ability.
That is what I thought. Thanks