Larian Studios Forums Baldur's Gate III Baldur's Gate III - Technical & Gameplay Problems Mage Armor does not change base armor for Barbarians

As a proper bug report. This should either be fixed or the description of Unarmored Defense/Mage Armor should be updated.

Title:
Mage Armor does not change base armor for Barbarians

Description:
Karlach was able to use a Mage Armor scroll that was acquired and has the buff applied to her character sheet, but the base armor remains at base 10 instead of base 13. By definition of Mage Armor and Unarmored Defense, Karlach should be able to use Mage Armor in conjunction with Unarmored Defense.

Repro Steps:
[1]Launch Retail Title > Save file with Karlach in party
[2]Give Karlach a Scroll of Mage Armor
[3]Selecting Karlach > Cast Mage Armor on self
[4]Open Character Sheet > Observe Mage Armor Buff
[5]Using T to examine, examine Armor Class and see Karlach's base armor is 10

Actual:
Karlach does not benefit from Mage Armor based off the description of the Mage Armor Spell

Expected:
Mage Armor increases base armor of 10 to 13 an any person not wearing armor per spell description

Impact:
This is going to cause players to lose magic attempting to make Karlach a more viable tank option. Either a provided explanation in the spell descriptions or changing the base armor to be adjustable by the spell would be nice.

I think Larian is being faithful to the 5e SRD, where Mage Armor and Unarmored Defense don't stack; whichever's the better one of the two is the one that gets applied, and 10+DEX+CON might be higher than 13+DEX.

The way AC is calculated, it will always take the higher value of the two.

The Barbarian feature could use a better description that clarifies that is sets your character's BASE AC to a new value.

I would normally agree with you, but it's not a Barbarian exclusive problem. In 5e, AC calculation is explained and tells you how things interact. You always take the highest value of AC amongst features and spells, certain items and spells can raise AC like normal, some can't, things like that. So honestly, not clearly explaining AC is the real problem.

And really, Unarmored Defense isn't changing your base AC. Base AC has always been 10+DEX modifier. The feature is treated the same as Armor calculation, but doesn't require you to use armor.

That's the problem. D&D is a game that's true to rules as written over feelings and guesswork., Larian overlooked that. Unarmored Defense in 5e rules states that it replaces armor class, not adds to it. BG3 does not. Which means the way both are written, they need to stack. The actual abilities don't stack normally and I said that in my post that it should be updated to reflect that. The way they're written is game is that Base AC for Mage Armor is updated from 10 to 13 if not wearing armor. Unarmored Defense states that if the barbarian is not wearing armor, their AC is Base Armor, plus Dex, Plus Con. By that definition, they should stack and a string fix is easy to do.

Wrong.

Unarmored Defense is by definition, an ability that only works with no armor. Mage ARMOR, as the title suggests, is magical armor, and does not stack.