Great Weapon Master gets you -5 to the attack roll and +10 to damage.
The way that extra damage is often implemented in this game makes this crazy.
Extra damage is implemented as an extra attack, that shares the same attack roll as the weapon attack.
Now i have a halberd, that deals an additional 1d6 lightning damage on hit.
And i have Colossus Slayer, which deals an additional 1d8 damage on hit.
So my Weapon hit deals 1d10+3(str)+10(gwm) damage.
The lightning damage deals 1d6+10(gwm) damage.
Colossus Slayer deals 1d8+10(gwm) damage.
together thats 1d10+1d8+1d6+33 damage if i hit.
That is the result of a poor understanding, how game mechanics work and how they can influence each other. Instead of making one hit roll and adding the damage together, 3 attacks with the same hit roll are made.
I know that this is a bug, but i bet, it will be fixed, by giving gwm bonus damage only to weapon attacks, instead of fixing the three attacks thing.
and that is what makes me sad about this game. it has so much potential. the story is great, the map is wonderful, everything is crafted with love, i think. but when it comes to game balance and how game rules work and interact with one another, larian has a big problem to understand, why things are in the rules, as they are in 5e.
you can see what i mean with the many complains in this forum, that larian doesn't stick to the 5e ruleset. and this bug is a direct result of this lack of understanding.
