I have a feeling that there are some bugs with damage resistance/immunity. In playing a Fall Further game with the Scions of Patria, I had strength 14 Wraiths with my 5 death mana, so they were 6+8death strength. Similarly for my Spectres. Displayed combat values were very low when fighting against undead or demon units that in theory were immune to death damage, as they should be. But the rate at which I was consistently winning fights with displayed combat odds of 0.3% and 0.5% makes me think that the death damage immunity was not actually being processed in the actual combat calculations. Similarly, I remember a while ago situations where I had open borders with country A and was at war with country B, and country B had open borders with country. Displayed combat odds gave Country B units in country A cities the defensive bonus from cities and fortifications, but the number of battles I won with frontal assaults of summoned units made me pretty sure that the defensive bonuses weren't actually being calculated. I don't know whether other damage bonuses or resistances actually help. IMO resistances should also reduce the max damage of spells; Maelstrom that normally damages a unit to 50% should only be able to damage a unit with 20% lightning resistance to 30%. Would be good if someone could test/confirm these results.