"Build a man a fire, and he'll be warm for a day. Set a man on fire, and he'll be warm for the rest of his life." ~ T. Pratchett
Dear Imperator I hope not.
@OP: For a second I thought this was a reference to the Daemonology thing that has had people going a bit nuts over. Considering that even Ezekiel of the Dark Angels can summon a Blood Thirster (speaking of which, why would Khorne even pay attention to such a witch?) then it might not be so far removed for some Boys-in-Grey to flirt with the dark side a little.
http://www.lounge.belloflostsouls.net/showthread.php?52423-The-Blood-Pact-Chaos-Homebrew-Supplement&p=472214&viewfull=1#post472214