Sorry if this has been asked before, but I can't be the only one having trouble figuring it out;

How exactly does Magic Resistance work?

What does it affect?

Obviously, I'm sure it affects spells, but can it only cancel spells, or negate effects. That is, will Magic Resistance protect a character caught in the blast radius of a fireball? Or will it only cancel spells directly targeting the resisting character, say...charm person or chromatic orb?

Does it affect Beholder eye attacks? A banshee's wail? Mind Flayer's abilities? I'm almost sure it doesn't do squat against breath weapons or magic weapons, but what about spell effects created by items (wands, etc)?

"Sorry if this has been asked before, but I can't be the only one having trouble figuring it out;"
Well, it's not exactly a question that floods the forum every month, so don't worry about it.

"How exactly does Magic Resistance work?"
The percentage of MR determines the chance a harmfull spell will be resisted (In BGI it also works vs helpfull spells) Individual projectiles are tested individually, so with magic missile each missile will be tested to see if it hits the target. On a side note: Some spells effects ignore MR.

"What does it affect?"
Harmfull spells. There are also scrolls of protection from magic which protect from all magic including spells which penetrate magic resistance like imprisonment.

"Will Magic Resistance protect a character caught in the blast radius of a fireball?"
Yes

"Or will it only cancel spells directly targeting the resisting character, say...charm person or chromatic orb?"
It will negate most spells like this

"Does it affect Beholder eye attacks?"
Yes

"A banshee's wail?"
Think so

"Mind Flayer's abilities?"
Nope, all mind flayers spells/abilities ignore MR.

"I'm almost sure it doesn't do squat against breath weapons or magic weapons."
When creating an item you can decide wether or not to let the weapon's abilities test MR, although most weapons don't.

"What about spell effects created by items (wands, etc)?"
Most items are tested, but not all. Wand of cloudkill for example is bugged and therefor ignores MR. This also works on enemies.

There are 2 kind of MR: Magic resistance and Magic Damage resistance. MR prevent you from spell's effect and MDR reduce spell's damage I think

I almost never seen magic damage resistance(but like the sound of it :D ) beside Valygars armor.
Anyone knows where such items could be found?? :confused:

The Belt of Inertial Barrier has a 50% magic damage resistance on it. It may be bought in Trademeet after you've done the Dao quest.

That's probably the only item with that ability everyone can use too.