Herne the Hunter
Herne is the Wild Hunter of Celtic and German myth. In the stories he flies through the sky or over the ground with his pack of demon hounds. His menace is prodigious — if the Hellhound is not in play, place it in Herne’s area!
He has Pack tokens and starts with tokens equal to the heroes. If his Pack drops below 3, he adds more in his Menace, up to a maximum of 6. If he has run out of Pack tokens, he places Fiends instead, so no matter what he has a sizable contingent accompanying him.
His Toughness is equal to 3 +1 per Pack.
So in a 5 player game, he’d start with a Toughness 8 which is pretty much unthinkably horrible. In addition, each Pack adds 1d12 to his attack (base 6d8). A Lord with Toughness 8 and 6d8+5d12 attack is lethal. Fortunately you can kill the Pack independently of Herne. Each Pack only has Toughness 1+1 and gives the killer 1 Courage.
While Herne also inflicts 1 damage on the hero with the highest Health when he attacks, his main threat is the Pack, so early on during the fight you are forced to kill his hounds, and only later do you target him directly. Of course you may also need to deal with a Hellhound and some Fiends.