Baldur's Gate 3 player uses D&D math to explain why Shadowheart's Firebolts always seem to miss

I recently started my second proper Baldur's Gate 3 playthrough since defeating the Brain earlier this year. As is pretty much par for the course, it wasn't long before I'd recruited Shadowheart, and as is also par for the course, it wasn't long before I was rolling my eyes as every single Firebolt she threw missed its target. 

Shart's wonky aim has been a talking point among the community for a long time, and while I assumed it had something to do with the fact that she's a support-based cleric rather than a dedicated battle mage, I'd never worked out exactly why she seemed so deeply incapable of hitting her mark. Of course, within the annals of the D&D rulebook there's a reason for everything, and one player has pulled out the answer to my specific conundrum.

Depending on your character creation choices, in the first few hours of Baldur's Gate 3, chances are you'll get most of your access to Firebolt via Astarion, Shadowheart, or Gale. While the latter picks up the Cantrip due to his wizardly powers, the two former Origin characters gets theirs from their Elven ancestry. Astarion is a High Elf, and as such starts with a Cantrip of Larian's choosing, while Shadowheart is a Half-Elf who takes advantage of her High-Elf Heritage to also take a Cantrip of Larian's choosing. In both instances, that's Firebolt, a simple spell that deals moderate damage, but which is also helpful for easily setting things on fire.

The thing is, most D&D spellcasters link their magical ability to a specific ability score. A Wizard, for instance, uses their Intelligence to enhance their spells, while a Warlock or Sorcerer uses Charisma, and Druids and Clerics use Wisdom. However, as noted on Reddit, when you learn Firebolt as a racial Cantrip, you're locked into using your Intelligence skill - for Astarion that number is a not-terrible 13, but for Shadowheart it's a deeply average 10.

With 10 INT, you get no bonus whatsoever to your attack roll from your ability class, and you're stuck with your proficiency modifier, which is only +2 at early levels. That means that if you attack an enemy with an armor class of 10, you'll hit 55% of the time. But if that enemy has an armor class of more than 10, you'll hit less than that. Through the first few hours, even the majority of lowly goblins you face have a higher AC than that, meaning the chances that Shadowheart's Firebolt's land are somewhere close to a literal coinflip.

Shadowheart has certainly suffered the community's ire more than Astarion, but I'll posit that has something to do with the latter's already excellent ranged damage thanks to his Rogue class and impressive 17 Dexterity, meaning that you don't have to rely on a relatively weak spell. What all this D&D math doesn't explain, however, is why Shart also seems to miss every mace swing, Guiding Bolt, or Sacred Flame as well. There are only so many turns in a row that I'd ideally be using Healing Word, so I'd like it if at least some of her spells hit.

Here's everything we know about Baldur's Gate 3 DLC so far.