Does the disease affect your demon? Even undead get the Diseased-affliction, but it has no effect whatsoever on them. After you have checked that, could please tell us how it works.
Originally posted by awafour: Basically, my question is: Are devils undead or not??
Devils aren't undead (you can tell because they don't have the "Undead" icon on their stat screen) but they do use Undead Leadership and not normal or magical leadership.
OK - playing a few turns revealed that the Devil is not really diseased, only the icon shows up.
Apparently, then, demons use undead leadership and can use equipment for the undead (without penalty) ... even though they aren't actually listed as undead.