My favorite part of playing old Baldur's Gate is how the spell system works.
So, intelligence actually doesn't matter that much. Intelligence determines how many spells you can learn (e.g. slots in the spellbook,) and determines the percentage chance for learning spells (All spell learning requires using a scroll; some of the time, you'll fail to learn the spell and waste the scroll). It doesn't determine DC or anything like that.
Also, once you've learned a spell like this, it's always going to be there, even if your int decreases.
Also also there are many ways to temporarily increase your intelligence.
So I made a Bard with low int, right? Since I'd played future editions where their spellcasting was governed by charisma - but in 2e, it's governed by intelligence! I set my primary casting stat to 12 without giving it much thought.
What's a very slutty bard of slightly above intelligence to do?
Well, if you're a magical shopkeeper in Baldur's Gate, imagine you see a cheerful didsheveled old Bard come in and spend three hours combing over your entire scroll collection. He buys as many useful scrolls as he can carry, plus three potions of genius.
He sits down right to the side of the counter. Snorts an impressive amount of modfinil/potion of genius. Binges on scrolls more complicated than you've sold in half a decade. One after the other after the other just inhaling magical secrets it took you years to comprehend. It's been 8 hours and instead of asking you for directions to an inn or even where he can get some water, he goes back to view your wares. Looks over the whole stock. Buys enough useful scrolls that he can only barely carry them. And three potions of genius, of course.
He sits down. Repeats the process. Now he's learning stuff that you know he won't be able to cast at his current power level. When you tell him this he says "Oh, I know, but I've gotta get the most out of these potions of genius. I'll just commit 'em to memory now and once I'm strong enough to cast 'em I'll know 'em!" And then he just. Completes the Bard curriculum. The most powerful Bard spells, he knows, even though he can't cast them yet. All of them. All the ones you sell, anyway.
He wakes up in the morning with the worst hangover of his life. An incohate sense of loss, as if his sight is dimmer, his comprehension less. His mind bursting with arcane secrets that he no longer comprehends but can absolutely still call upon in battle.
He leaves the poor shop staff a 100 gp tip and collapses in the softest bed in the most luxurious inn in Baldur's Gate.
A week later, you see a wanted poster, for treason. He looks much better put together than he did when binging nootropics and arcane scrolls, but that's definitely him. A week after that, he's the hero of Baldur's Gate. A week after that, he's a Bhaalspawn. You wonder what he'll be next week.
