[Sombre]

Hmm, I don't think we can really apply rules to 'chance to get diseased'. It depends where the disease is coming from. Some spells and weapons involve an mr check or hit a certain % of things, etc then there's old age, disease spreading sites, ctis miasma, random unit creation afflictions (ala flagellants). I think each of these should be regarded in isolation from the others. For instance the weapons which specifically cause the disease affliction don't care about age, death magic, regeneration etc. They only care about whether they check mr or not (one does the other doesn't). Meanwhile a site might be a flat 5% chance for every unit in a province to get a disease each turn - that may or may not be modified by regeneration or death magic or any of the factors that play into disease from old age or disease as a battle damage generated affliction.