I believe the answer is yes, the protection of some items, spells, scrolls, etc. is accumulative and that through this effect you can gain 100 % immunity to the respective type of damage. But that depends very much on the individual item and spell. Read the descriptions carefully, other than that go by trial and error.
Good luck !
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So long !
R³ aka "The Ramonster"(thanks Sir Tainly) - proud to be the official spokesman for the most noble Lady Bilqis, Desert Rose of Ironworks
Btw, the cow is queuing in the slaughterhouse right now !