@JeremyECrawford Great Weapon Fighting and Battlemaster' Sweeping Attack: may I reroll the 1 and 2 of the superiority die?
— Matteo Gama Galli (@Il_Gama) April 22, 2018
Great Weapon Fighting works only with the damage dice of the qualifying weapon. #DnD https://t.co/Aj22UfGiet
— Jeremy Crawford (@JeremyECrawford) April 23, 2018
What if you’ve got a weird situation like a greatsword flametongue or frostbrand? Still only the 2d6 from the greatsword? Those are weapons. Their dice are affected.
— Jeremy Crawford (@JeremyECrawford) April 23, 2018
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? Yes. The description of the flame tongue (the weapon) even says the sword deals the extra damage.
— Jeremy Crawford (@JeremyECrawford) April 23, 2018