Aligned Spell Proficiency

So my setting is very Moorcockian with Law, Chaos, and Balance as viable PCs and antagonists (being chaotic =/= gribbly insane and evil in my world).

So I was thinkimg about proficiencies that might let a caster have greater effect versus their opposites…so something like Lawful Casting: Chaotic targets suffer a -1 to saves versus your spells. Balance characters might pick a specific alignment to target (or lawful and chaotic inflict a -2 and balance gets a -1 vs both).

What do you think…too powerful? Not powerful enough?

The closest analogue would be something like Black Lore of Zahar that gives -2 to targets of all your death saves. on the one hand you’re affecting ALL of your spells, but on the other hand it’s usable against only people of certain alignment. On the OTHER OTHER hand, it could be like smite evil where you can be reasonably assured a good number of your foes will be the right alignment. My gut tells me it would be ok, though, since -1 to a save is only a 5% swing, so it will matter for 1 in 20 spellcastings at best.

I think -1 and a minor secondary benefit of some kind would be the best option.

It’s my feeling that if it were -2, every spellcaster would feel that they have to take it, since most enemies you fight will be opposed to your alignment.

On the other hand, being just a straight -1, I don’t feel like that would be impactful enough for a proficiency slot.

I guess I don’t like Balance picking only one or the other, as they should be opposed to both…however giving them a flat -1 to both is out of whack if the others only get a -1 to their opposite.

What might be a good power to boost these if I went with just -1?

Presumably Law and Chaos are each opposed to Balance, as well as each other, though - why shouldn’t Lawful Casting yield -1 to save vs. spells of both Chaotic and Balanced targets?

You could do some stuff with expected value, like Chaotic casters increase die sizes by 1 but also subtract 1 per die, while Lawful casters decrease die sizes by 1 but add one per die (so 5th level Lawful fireball → 5d4+5, 5th level Chaotic fireball → 5d8-5). Same expectation, greater or lesser variance.

how about:

Law: Chaos saves against you at -1
Chaos: Law saves against you at -1
Balance: You save at +1 vs. law or chaos

I’d say that Balance is simply that… “balanced”. It gets no modifier (and by extension, doesn’t need a proficiency).