Hidden partial resists to nether?

[Zikke]

I am finding that many monsters at which I shoot Rend Soul (which is labelled as a nether bolt in the description) is "resisted somewhat" by creatures that I would think have no business resisting it, such as trolls or some humanoids. I play with the full monster memory and it says they "do not resist nether".

Is this spell not truly a nether spell? How could things resist it if they don't resist nether? Do uniques have some resistance to this?

[Nick]

All evil monsters take half damage from nether - it's meant to be a force-of-the-underworld thing.

[Zikke]

Ah, gotcha. That sounds familiar now that I think about it some more.

[Timo Pietilä]

All evil monsters take half damage from nether - it's meant to be a force-of-the-underworld thing.

That's why undeads are immune taking no damage at all.