I'm coming at kit modding as a rank amateur here - I basically tweaked a few existing kits in NI (and even that took me forever, since I don't have a lot of time to learn how to mod) and it's given me ideas probably way above my station... especially since I am clueless with WeiDu and would have no idea how to add a new kit to the game.
I'm really interested in creating a sort of Arcane Trickster style class. I'm aware that the Mage/Thief exists, but I'd quite enjoy having something that gets a handful of fewer 'innate' spells (and doesn't just turn into a mage first with a bit of thief utility as the game goes on) with the sort of focus on Enchanment that, well, Enchanters get with some illusion utility to really take advantage of that backstab ability too. Plus they get to benefit from the fast Thief levelling. I think it'd just make a weird, but not too OP combination that feels a bit more like a sneaky, tricky Wizard.
Anyway - to the point - what I really want to know is if it's possible to give this potential kit an ability such that casting against an 'unaware' target gives them a penalty to shrug off any 'save-or-else' spells, similar to how targets get a -4 to AC when you're attacking them from stealth. Maybe - if that's not possible - just a bonus if the caster is hidden or invisible or something?
I wouldn't really know where to begin with actually doing it, but as I said my time's really quite limited (and I'd rather use my precious few hours to play the game than mod it!) and I want to know if it even IS possible before wasting hours trying to accomplish it when it might not be.
Help super appreciated