The wizard whose town you reclaimed is grateful and elated, but these emotions soon pass as he realizes that without retribution, his kingdom will come under constant fire by would-be usurpers. He offers mastery of the secrets of death to whoever can unseat his former conqueror.
The first scenario in this campaign was posted about a month ago and the third and final one will be released soon.
In other news, Loco_Blutaxt from the official forums has made a useful little excel file which is a checklist for all the cards in the game. If you play the game then do check it out, it's a nifty little thing.