Nightshield vs. Shield

[Thalone]

For as long as I can remember, I have favoured Nightshield over Shield for immunity to magic missiles. I would prefer using Shield instead (because I learned some time ago it has a component which decreases incoming grazing hit damage), but was prevented from doing so due to its ASF check, whereas I've never had to roll against ASF scrolling Nightshield over dozens of lives with heavy armour on.

I finally started a Warlock life today, and by chance, I looked at the tooltip for Nightshield and it has a somatic component.

The heck?

Wiki says: "Arcane Spell Failure (ASF) is the chance that an arcane spell — that is, one from the Sorcerer/Wizard spell list or Bard spell list — will fail to be cast due to interference from the caster's armor or shield."

Both Nightshield and Shield are on the arcane spell list, both have somatic components. Why don't they both suffer from ASF in practice?

[slarden]

For as long as I can remember, I have favoured Nightshield over Shield for immunity to magic missiles. I would prefer using Shield instead (because I learned some time ago it has a component which decreases incoming grazing hit damage), but was prevented from doing so due to its ASF check, whereas I've never had to roll against ASF scrolling Nightshield over dozens of lives with heavy armour on.

I finally started a Warlock life today, and by chance, I looked at the tooltip for Nightshield and it has a somatic component.

The heck?

Wiki says: "Arcane Spell Failure (ASF) is the chance that an arcane spell — that is, one from the Sorcerer/Wizard spell list or Bard spell list — will fail to be cast due to interference from the caster's armor or shield."

Both Nightshield and Shield are on the arcane spell list, both have somatic components. Why don't they both suffer from ASF in practice?

My best guess is that nightshield is also a divine spell while shield is only granted to arcanes. It's speculation but that is what I think.

[Arianrhod]

I may be remembering wrong, but I think when Nightshield was first introduced it was (only) a cleric spell, so it may have been coded way back then to disregard ASF. Sometimes weird stuff happens in old games ;)

[HastyPudding]

Shield is better than Nighshield, anyway. Nightshield gives a resistance bonus to saves...but it doesn't stack with resistance items. Shield, however, at least gives a shield bonus to AC, which stacks with every other form of AC except other shield bonuses.

[Thalone]

Thanks for the responses... it seems slarden is correct. I picked up some scrolls that are in both the divine and arcane books and cast them on my barb. Protection from Evil, Obscuring Mist, Cause Fear, Resist Energy, Spawn Screen, and Bear's Endurance all have a somatic component, and I never had to roll for ASF in medium armour.

Everyone exploit the divine scrolls as necessary...

[nibel]

Shield wands are sold in the guild wand vendor, and do not suffer ASF at all, compared to the scrolls.

On the other hand, they only have a durability of 5, and at high levels break very often. Because they are bound, they never take permanent damage, but if they are broken, you can't cast from them until you repair.