[Aleph]

The Eater of the Dead starts out under your control, but, as you might guess from the name, he eats dead. This makes him stronger. After some amount of this (I have no idea what the corpse count has to be), he becomes an independent terror, running around attacking provinces at random. I think the main strat for him is to Gift of Reason him (IIRC he starts as a rank and file), load him up with nasties, and push straight into enemy territory. That way, when he goes bonkers, his rampages will still work out in your favor.