What effects do adjustments to "spell mastery" do?

No, it's not increase damage spell, this only help to overcome enemies resist like slow enemies down, or freeze, something to debuff or weaker enemies without damage, I could be wrong...

I'm pretty sure it's a straight forward +2 SM => -2 to chance enemy will resist a spell.

+2 spell mastery is maybe .5% damage depending on the mob I suppose. It's not a very good trait or buff to an item. I like the +10 damage robes much more than the +10 spell mastery robes for example. I do take the plus spell master per level trait on character creation though.

If your mage uses debuffs like Blindness then Spell Mastery helps with landing the effect on the target.

Spell Mastery is what decides if a spell is resisted or not.

When you cast a spell on an enemy that can be resisted, the game takes your Spell Mastery and deducts the target's Spell Resist. The number you get is the chance that your spell will not be resisted.

75 Spell Mastery vs 20 Spell Resist = 55% chance that your spell will not be resisted if it can be

It depends on the role of your champion.  If you are a tamer or a debuffer, the mastery is a lot more useful.  If you are a direct damage dealer, the damage boost is usually, but not always more useful.

Thanks, that makes sense. but does +2 literally mean 2 points or does it represent a multiple of some number?

For example would +2 raise the mastery in your example to 77, or would it raise it to 85 (where each +1 would equal a multiple of 5)

+2 is just +2.  So 77 would become 79.

Thanks! I don't think I'm going to waste my time pursuing spell mastery adjustments/bonuses, if all you get is +1 here or +2 there.

Doesn't seem worth it.

They're crucial to me as you'll face enemies with 40-50 spell resist at the end of the game.

Yeah, you can't waste 5 turns trying to cast blindness or shrink on a dragon with a 20% to get the spell through.

eh, magic resistance is usless against an enchanted sword.

Stormbringer or vorpal blade anyone? :>) Just some modding ideas...

By then you should have a defender with 100% fire resist and big dodge, defence and HP.

I think it comes down to personal preference.  Some people like to burninate their enemies, others to chop them into pieces.  Fallen Enchantress allows both.

Personally, I like the chopping better.

Like this? http://stormworld.wikidot.com/reliquary#Vorpal_Sword

awesome!

Bear in mind that there's the Brilliant trait that you can pick for your sov at creation, +2 Spell Mastery per level, not to be sniffed at.