Ok, I actually know the answer to this. They're Dwarfs caught in some sort of Chaos storm/incursion/influx. I also know they make powerful chaos-fuelled weapons and that they take slaves...

Quote Originally Posted by Damien 1427
Now, the Chaos Dwarves, in the past, bred the black orcs which were stronger, more intelligent and far more aggresive on average than the standard orc.
I joined the hobby about two years ago, I've read everything I could find on the Warhammer world, but exept for being mentioned in 'Storm of Chaos' and 'Ogre Kingdoms' there is no information on the evil Dwarf-things. I want to know, please tell me, please... It's driving me mad... aaargh!