"Mousillon is a city and former Dukedom of Bretonnia. Mousillon is a cursed realm, a crumbling city surrounded by stinking marshes and swamps, a land that is shunned by the rest of the country. It is said that in that doom-laden land the dead walk the dark and empty streets, that all manner of unnamed horrors lurk in the depths below castles, and that the night is filled with screams and laughter from beings no longer of this earth. Those dwelling there are the most desperate of people, for none would choose to live in this tragic land other than the evil-hearted and the outcast. Dispossessed and dishonoured knights band together here, as do hordes of the most malformed and diseased peasants. Those few who remain of the cursed bloodline rule this land with absolute authority. These remnants of the decadent and corrupt nobility wear pitch armour, and never raise their visors, or so it is said in fireside tales. The implication is that the nobility of Mousillon have been corrupted by vampirism."
A word from ntdars; The Mousillon supplement was created by the Strike To Stun team (alongside their Karak Azgal supplement) way back in the day and offers some awesome content and warbands. If you aren't familiar with Mousillon, it was once a Bretonnian city that fell to evil and corruption. The style and feel of this campaign is much like Mordheim itself; dark and brooding. Mousillon Website.