I'm not level 23 yet so can't test it myself, I have a couple questions about scales of the dragon:
1. If your dragon type is shadow and you're in PM undead form, since it blocks 50% of negative does that mean it also cuts death aura healing by half?
2a. Does scales of the dragon negate only physical damage or also elemental damage?
2b. If it also negates elemental damage, does it get used up before or after protection from elements?
3. Does it get used up before or after stoneskin's 10/ada dr is calculated?