i think sallow man's debuff can only be removed by bless and (mass) cleanse wounds
keep in mind that you have access to stuff like arrow storm, hailstorm and pyroclastic eruption at your disposal, plus any other source spells can be used free of charge. it's not like any other fight in the game and other rules and restrictions that applied to other difficult fights are waived away in this one. go crazy, use your strongest spells, don't pull any punches
also, figure out which characters are best focused over others. the fight may be easier than you think
