It seems that there is always unfinished business between Denegra and Karchev. A while ago, the wraith-witch and her allies attacked Kharchev's foot-hold in Steamtown.
Each side was charged with seizing and objective, or taking out the enemy caster.
By the end many jacks had become scrap. The Khador objective was contested, while the Cryx objective was held firmly by the wraith engine. The human forces were scattered and the undead were left to their own plots.