Neither of these are hardly an uncommon spell, but they do seem to generate a fair bit of confusion from time to time. I don’t pretend to be the final word on interpreting B/X D&D, but it is a game I spend a fair bit of time pondering.
Depending on how you count things, there are two to four spells in this category:
The “personal” vs the 10’ radius and the Clerical vs MU/Elf versions. For the purposes of this Random
Spell(s) Assessment, we’ll just be (mostly*) looking at the former.
Starting off with the first one of these spells that players are likely to get their hands on, there is the
classic: Protection from Evil.
(from Moldvay)
Cleric 1/MU 1
Protection from Evil Range: 0 (caster only)
Duration: 12 turns
This spell circles the cleric with a magic barrier. This barrier will
move with the caster. The spell serves as some protection from
"evil" attacks (attacks by monsters of some alignment other than
the cleric's alignment) by adding 1 to the clerics' saving throws, and
subtracting 1 from the "to hit" die roll of these opponents. The
spell will also keep out hand-to-hand attacks from enchanted
(summoned or created) monsters (such as living statues), but not
missile fire attacks from these creatures (see COMBAT). The cleric
may break this protection by attacking the monster in hand-to-hand
combat, but still gains the bonus "to hit" and saves.
*Both MU versions are nearly identical to the clerical versions, so there’s no need to list both descriptions here. The one big change is that the duration for the MU 1st level spell is half that of the clerical: Six turns instead of twelve. I guess those arcane types aren’t getting a divine assist. Everything else is the same.
There is a fair bit to unpack in this description, so let’s dig in, shall we?
In essence, the spell creates a sort of force field around the cast that blocks or limits attacks by “evil” creatures. Since this is BX, there is no “Evil” alignment, just Law, Chaos, and Neutrality. As in the “Detect Evil” spell, evil is defined as a differing alignment having an “evil” intent (malice, etc.). So a Neutral Elf would be protected from lawful or chaotic beings wishing him harm, etc.
The first effects listed are pretty straightforward. The caster gets a buff to saves and the baddies get a penalty to attacks (+1/-1). The next part is interesting, though.
“The spell will also keep out hand-to-hand attacks from enchanted (summoned or created) monsters (such as living statues), but not missile fire attacks from these creatures (see COMBAT).”
This point is probably where I see the most confusion from people: Notice that the stuff about differing alignment is no longer in play here? That chaotic chieftain is getting a -1 to hit you, but he can absolutely try to smash you in the face with his battleaxe. That Bone Golem? Not so much. This is an important distinction. I’ve seen games where this wasn’t clear to the group and a lot of confusion arose about how exactly the baddies could do anything to the caster after this measly 1st level spell was in effect.
The next thing to remember is that the caster cannot engage in melee combat with the warded monster without breaking the effect. It doesn’t say anything about missile fire, though. Also, the +1/-1 is still going even if the force field is gone.
The area of effect version is pretty much the same, except it can protect more than one person at a time. It’s also the only way to put the effect on anyone else (both spells are centered on the caster, no other target is valid as written).
(from Cook)
Cleric 4/MU 3
Protection from Evil 10' Radius Range: 0'
Duration: 12 turns
This spell circles the caster with a magical barrier that will protect
all friendly creatures within 10' of the cleric. This barrier will move
with the cleric. The spell serves as some protection from "evil"
attacks (attacks by monsters of an alignment other than the
caster's) by adding 1 to the caster's saving throw and subtracting 1
from evil opponents' "to hit" roll. This spell will also keep out
melee attacks from enchanted monsters (such as elementals) but
not missile or magical attacks from these creatures. Enchanted
monsters can melee if any of the protected creatures attempt to
attack them with hand-to-hand combat.
(Once again, the MU version is weaker in that it’s a higher level spell than for clerics. Otherwise, no differences.) The new takeaways from here are that multiple people are protected, but only if they stay close to the cleric, and that if anyone even tried melee with the warded monster(s), they can ignore the force field effect in general (“...if ANY of the protected creatures ATTEMPT to attack them with hand-to-hand combat). This means not only that INT 6 fighter could negate that protection with a swing and a miss, he dispels the field for *everyone*. Again though, missile fire is fine for some reason. I guess it’s a look don’t touch kind of thing?
Now, there is some ambiguity regarding the nature of the 10’ radius field. Part of the text seems to indicate that it simply creates a protective field for all the people in the radius, other parts make it sound like it could be used to block a corridor or similar. Personally I’m inclined to the latter, as a 3rd-4th level spell should have a little oomph, IMO. Also the idea that one person attempting melee dispels the effect for all makes it sound like one big field, not multiple personal ones. Fun tidbit: Remember that the alignments you are protected from are determined by the caster’s alignment, not each individual friendly getting the effects. So if a lawful cleric casts it on the party, it won’t grant penalties or bonuses vs. lawful for that neutral thief.
The duration for both of these spells are obviously applicable over more than a single combat. However, given how easily the “force field” can be dispelled, it seems that the +1/-1 is the more durable benefit. Smart timing could grant those receiving the spell’s benefits with a nice little modifier as they move into an area where they expect to be butting heads with folks of other alignments. Entering Area K in the Caves of Chaos would be a great example of when to use it!