It doesn't seem to be obvious from in-game descriptions but I was always under impression that shadows are moving by surfaces but never through them. Might be wrong though, but it could explain why they don't have such ability in game.

I suppose should be RFE, not a bug.

I agree on the immunity to cold. Fixed.

The cloud description of wraiths was meant to indicate a modicum of physicality. Thus they won't get the ability to pass through walls.

cool - now spectres and ghosts should be usefull in ICD Levels

What about revenants and spectres. Do they get ability to pass through walls too ? For sure they look like ghosts in game.

how it is now in v. 3.0.6:

Cold immunity seems to work well now on some of undeads, but now:

Vile Spirits, Wraiths and Ghosts (all) are the the only undeads that have ability to pass through walls.

How it should be:

Wraiths should not pass through walls (as You stated before),

Please give that ability to higher tier non-coporeal undeads:

- Spectres (they are high on necromancer undead slave list - not giving them that ability is making them rather questionable choice)
- Shadow Lords (they are very high on necromancer undead slave list - PV 0 - they leave no corpse - from description its hard to tell if they have physical form)
- Revenants ([...] An aura of malice surrounds this ghostly figure [...])

All mentioned above undeads seems to not have physical form.

Fixed the wraiths. Revenants in my mind always have been rotting hateful corpses so I adjusted the description. Shadow Lords are more shadows than anything - so in my book they shouldn't pass through walls.

Spectres... well... now they do.