Remember that movie about the guy who wanted revenge for the death of his son and had a monster unleashed that he could not control? I can't remember the name, but the warning is the same. Dabble in black magic and it could come back to bite you.
That's all I can say about this movie. Thai Black magic and some really gory stuff. The problem is that it takes a lifetime to get there, and the trip is very painful. Painful in the sense that there wasn't anyone in this film that resembled an actor.
If it's blood you are fishing for, then you'll catch it, but at what cost?