Just had an amazing moment in my Brettonian fort. A veritable horde of dark stranglers and beakwolves were gathered outside my walls whilst my men cowered, attempting to assemble arms and armour to sally forth some time in the future.
Out of nowhere, I get the message saying that Zilta Boundrelic, a Juggernaut of Khorne had arrived (a semimegabeast) and it began a rampage of pure carnage through the besieging ranks. It sent one beakwolf sailing 12 tiles to slam into a wall, bursting on impact. All the attacks directed towards it glanced away harmlessly. A dozen dead enemies later, its only wounds were shattered eyes and incredible exhaustion. I look forward to it's fights against better armed opponents and, later, against my Brettonians, who shall try and slay the fell beast in the name of the Lady!
EDIT: Well, as it is blind, the Juggernaut stumbles drunkenly after a wave of migrants, only catching them after a siege arrived (which it massacred as they foolishly got within the reach of its deadly horn) and scared them into a corner. One of the bastards tried to be brave and punched its hoof (to no effect) and was promptly put to the ground and gored to death. It also managed to kick a different migrant in the head, shattering his skull but luckily not killing him.
As the migrants have been outside for so long, constantly fleeing the beast, they are very drowsy, dehydrated, starving, and very unhappy. They are gonna make some mean ghosts...
EDIT 2: All of the migrants just died of terrible thirst. And another Juggernaut just showed up. This one is named Tamer Faithhook and is not crippled by a lack of eyes. I fear for the future of this fort...
EDIT 3: Another wave of migrants was brutally slaughtered by this newest Juggernaut. I'm half expecting another of the daemons to arrive this next year xD