To put it more simply, imagine your Physical defenses. You have Thrust, Stab, Slash to defend against.
Now imagine that with magic, one defense for pure magic and one defense for Dark Magic.
I'm bringing this up because we all know that Dark Bead outdamages CSS when all the Beads connect, but I recently noticed that against certain enemies with higher Magical Defense, the CSS would actually do more damage than Dark Bead, sometimes an overwhelming amount more (in one of my cases I was hitting around 220 with Dark Bead and my CSS would do around 350, a huge increase in damage).
So I began to wonder just how that worked, basic math tells us that decreased damage on a spell would just mean that another STRONGER spell would also have decreased damage, but would still do more damage than the first spell. Yet in this case, the weaker spell was outdamaging the latter.
Then another idea came to me. Is magic defense percent based? Think about it. If you go to the DLC you'll find that although magic damage has very little effect on the bosses, pure magic will still do a considerate amount of damage, yet Dark Magic does practically nothing to the very same boss.
So now I'm curious as to whether Dark Magic is affected by a different defense rather than magic. It may in fact be doing magic damage but said magic damage is reduced by a completely different defense, such as physical (just to give an example). In that case, higher defense in X area would make you receive less damage from Dark Magic, although it still does magic damage.
But then there's the case of the Magic Barriers. If Dark Magic is indeed affected by some other type of defense, than the Magic Barriers should have no effect on it as they only protect from magic.
I don't really know where to go from here, so I was going to test this but I don't have the time to do so. Just think about this, can anyone really tell me that Dark Magic is not affected by some other type of defense? Maybe a hidden modifier?
Again, just an idea. I may just be paranoid.