So the weapon damage die is 2d6 and that is clearly affected GWF
Vicious weapons do an additional 2d6 damage, this is less clear if it's affected by SAC entries on GWF. I would lean on this being a no as it's an enchantment rather than the base weapon die but I could see this one going either way.
Battle Mastery Manoeuvres 1d8 would not be affected GWF
Goliath's Fire's Burn 1d10 would not be affected by GWF
@Il_Gama Great Weapon Fighting and Battlemaster' Sweeping Attack: may I reroll the 1 and 2 of the superiority die? @JeremyECrawford Great Weapon Fighting works only with the damage dice of the qualifying weapon. @<> What if you’ve got a weird situation like a greatsword flametongue or frostbrand? Still only the 2d6 from the greatsword? @JeremyECrawford Those are weapons. Their dice are affected. @<> Sorry, to clarify just in case. 2d6 slashing +2d6 fire (for example). The 2d6 fire damage dice are re-rollable as they are weapon dice? @JeremyECrawford Yes. The description of the flame tongue (the weapon) even says the sword deals the extra damage.
If we want to follow that ruling, GFW should interact with Vicious Weapon and similar magic weapons.
(2024) Does GWF only affect the base weapon or does it also affect rider dice?
Example: Battle Master Fighter with fire giant strike and a Vicious Greatsword doing 2d6+2d6+1d8+1d10.
Would it only apply to the initial 2d6 or all of it?
So the weapon damage die is 2d6 and that is clearly affected GWF
Vicious weapons do an additional 2d6 damage, this is less clear if it's affected by SAC entries on GWF. I would lean on this being a no as it's an enchantment rather than the base weapon die but I could see this one going either way.
Battle Mastery Manoeuvres 1d8 would not be affected GWF
Goliath's Fire's Burn 1d10 would not be affected by GWF
Thank you! I somehow completely missed that entry well trying to figure this out.
While not official ruling, I shared in Savage Attacker, Great Weapon Fighting and extra damage dice this conversation with the Dev (link to sageadvice.eu) mentioning Flame Tongue and Frost Brand:
If we want to follow that ruling, GFW should interact with Vicious Weapon and similar magic weapons.