How does the Battle Master fighter's Sweeping Attack maneuver interact with additional damage dealt on a "hit"?

Question

How does the Battle Master fighter's Sweeping Attack maneuver work with extra damage, both rolled and static?

The description of the Battle Master fighter's Sweeping Attack maneuver states (PHB, p. 74; emphasis mine):

Sweeping Attack. When you hit a creature with a melee weapon attack, you can expend one superiority die to attempt to damage another creature with the same attack. Choose another creature within 5 feet of the original target and within your reach. If the original attack roll would hit the second creature, it takes damage equal to the number you roll on your superiority die. The damage is of the same type dealt by the original attack.

The description is very specific with the damage the 2nd target receives; in particular, it leaves out any bonus to your damage from your ability modifier. That leads me to think all other bonuses are also ignored, but I just want to confirm.

Specifically, I'm wondering whether the Great Weapon Master feat's bonus damage applies. The second benefit of the Great Weapon Master feat says (PHB, p. 167):

• Before you make a melee attack with a heavy weapon that you are proficient with, you can choose to take a -5 penalty to the attack roll. If the attack hits, you add +10 to the attack’s damage.

I've looked at some other questions regarding Sweeping Attack. It seems like the 2nd hit is not necessarily an attack, so if that's the case, then the wording in the feat "if the attack hits" could make it so the additional damage from Great Weapon Master does not apply to the 2nd target.

But what about enchanted weapons? Would a simple +1 weapon apply the +1 damage bonus to the 2nd target? How about something more complicated, such as the flame tongue?

The description of the flame tongue reads, in part (emphasis mine):

While the sword is ablaze, it deals an extra 2d6 fire damage to any target it hits.

Does the verbiage "any target it hits" imply or require an attack? Or does that bypass the attack rule?

Answer 1

Probably not.

Making "a hit" is not the same as dealing damage. A hit is specifically the result of making an attack roll.

Sweeping Attack doesn't make an attack against the second target; rather it says, "if the original attack roll would hit the second creature". It's just comparing your prior result and dealing some damage.

I would say Sweeping Attack doesn't trigger any of those secondary effects such as Flame Tongue's fire damage or Great Weapon Master. Some weapons have some rare but devastating secondary effects (usually based on rolling a 20), and you can trigger Sweeping Attack after you know what your die result was, so being able to include an extra target in the effect is probably not what's intended here. As an example of how crazy this could be, just imagine using this with a Vorpal sword -- you already know you rolled a 20, so at that point you can trigger Sweeping Attack to just automatically decapitate another enemy? I think not. (Similar if slightly less absurd issues are present with similar weapons, like the Sword of Life Stealing or Mace of Smiting.)

As to +1 weapons, I'm unsure. It says you get a bonus to "damage rolls made with this weapon", so it seems like it ought to apply, but I could see arguing that the weapon isn't really involved since you're rolling a superiority die for damage, not the weapon's damage dice.

But since it's not likely to cause a big balance issue, as a DM, I'd probably default to the benefit of the players in the absence of a clear answer. A couple extra damage on a sweeping attack won't break the system, so it's probably better to let the player have their fun and not get bent out of shape over the question.

Answer 2

it takes damage equal to the number you roll on your superiority die

… is completely unambiguous. It takes that damage and no other.