It seems to me that armor (at least from shields) is ignored by various shadows.
For example, in The Chamber of Insanity or Tomb of the Shadow King using shield didn't give any noticeable result.
With Ghost touch Greatsword it was much easier to survive (because I killed them before they can touch me) than with Ghost touch Dwarfaxe + Shield, while in other quests of similar level I've got almost no damage when I was with shield (I mean melee damage here, i.e. monsters almost always misses, but fireballs still burn me of course ).
Maybe those Shadows/Ghosts have very high attack value?
(which is similar to ignoring armor)
Please confirm or deny it.