Way back in 1991 a little one-shot magazine was published, "The Hero Quest Winter Special".
It was a joint production by Marvel, Games Workshop and Hasbro and it included expansion ideas and cut-out tiles to add to the game. It also included new monsters in the form of Skaven asAdvanced HQ was newly released and it was a great way to tie them in together.
I've used my copy to put together a monster card for printing, this is currently a WIP and I'll improve the quality later if folks like the idea.
|Skaven Warrior Monster Card|
Obviously, any of the Skaven Warriors produced by GW would be suitable for the game.