baldurs-gate-3
I noticed that different Quarterstaves have different damage amounts listed. I understand weapon damage affects how much damage physical attacks do, but how does it work for magical classes like Sorcerer that usually use spells instead of attacking directly? Does the damage range on my equipped weapon (a Quarterstaff) effect how much damage my spells do?
This is one instance where Baldur's Gate 3 differs from 5th edition.
The short answer is: the attribute used is whatever it says the attribute is when you're picking it.
For Gale, as a Wizard, this means INT. For any spellcasting class, it seems to use whatever your primary class' spellcasting ability is. (WIS for Clerics / Druids / Rangers, CHA for Bards / Warlocks / Paladins)
For anyone without spellcasting, it seems to use INT.
After some experimentation, I conclude that no, harming companions indirectly with Warding Bond does not affect their approval. They complain, but the complaints are inconsequential.
First, I'll note that the approval is available as a number, just in a different part of the UI than where I was looking. Specifically, in the "details" tab, it's near the bottom:
Checking this number after each action, I discovered:
Direct damage does affect approval. If my main character hits Shadowheart with three melee attacks (even fists), she will lower her approval by 10, and a message "Shadowheart disapproves" appears briefly in the center of the screen (not in the corner like for dialogue). Missed attacks have no effect on approval.
Complaint dialogue lines ("Watch it, oaf!") have no connection to approval. Any time she takes damage or is attacked (even on a miss) and attributes the source of damage to my character, she has about a 25% chance to speak a complaint line. (I didn't test with other companions doing damage.)
Damaging her indirectly with Warding Bond never affects approval, regardless of whether the damage is environmental or from an attack, and regardless of whether the damage incapacitates her.
Best Answer
Put simply, no.
Spell damage is calculated based on the dice shown on the spell - see this example from the Baldur's Gate wiki. A fireball will do 8d6 damage (increased based on upcasting) irrespective of the weapon you're holding.
The dice you're looking at on a weapon relate strictly to the damage done with melee or ranged attacks with that weapon (and will be affected by strength / dexterity as with other weapons.) Some weapons, like the Mourning Frost, add additional melee damage, but this has no direct effect on spell damage. A spell is not a weapon attack and therefore has its own damage dice.
Notably, there are certain weapons that will have indirect effects on spells - such as the Spellsparkler which grants you lightning charges on a successful cast. In fact, the Mourning Frost you linked has a special effect that deals 1 additional cold damage, and this is triggered on the caster dealing cold damage by any means, and affects cold damage from any source, including a spell.