The Artillerist artificer has the Arcane Firearm feature, which says in part (ERLW, pg. 60):

When you cast an artificer spell through the firearm, roll a d8, and you gain a bonus to one of the spell's damage rolls equal to the number rolled.

I'm trying to understand how this interacts with spells that (can) have multiple targets:

  • How does this affect spells with multiple rays? Do you just add a d8 to a single ray?
    For instance, scorching ray has the caster make a ranged spell attack for each ray, normally doing 2d6 fire damage on a hit. So would one ray of the player's choice do 2d6+1d8 damage, and the rest do 2d6?
  • And what about spells with an area of effect? Does it add a d8 to every creature's damage taken (before any halving from successful saves, etc.)?
    For instance, fireball deals 8d6 fire damage on a failed save (halved on a success). So would all creatures in the area take 8d6+1d8 fire damage (or half of that if they pass the Dex save)?

1 Answer 1


Gain a bonus to one of the spell’s damage rolls.

The Arcane Firearm feature says:

When you cast an artificer spell through the firearm, roll a d8, and you gain a bonus to one of the spell's damage rolls equal to the number rolled.

Whether a spell requires you to roll damage once or multiple times, choose one of those times. Add the result from the d8 to that damage roll.

Scorching ray involves multiple separate damage rolls, once for each hit, so you would add the d8 only to one of those damage rolls (see this Q&A for more details on this point: How many times do you roll damage for Scorching Ray?).

You roll once for area-of-effect damage (and magic missile).

The rules for damage rolls say:

If a spell or other effect deals damage to more than one target at the same time, roll the damage once for all of them.

So you would add the result of Arcane Firearm's d8 roll to the damage dealt to all creatures within the area of effect of fireball as well as each dart from magic missile.

  • \$\begingroup\$ Maybe I'm missing something, but: are you sure your reference to magic missile getting Arcane Firearm damage is correct? I can't figure out how that'd work, seeing as magic missile isn't on the artificer spell list and isn't granted by the artillerist subclass. Arcane Firearm specifies that it only applies the extra damage to artificer spells. \$\endgroup\$
    – screamline
    Aug 19, 2021 at 2:43
  • \$\begingroup\$ @screamline Armored Artificers get magic missile at 3rd level via the Armorer Spells subclass feature. So yeah, not applicable in the exact situation, but the general principle about how many times your roll damage is worth noting. \$\endgroup\$ Aug 19, 2021 at 4:30
  • \$\begingroup\$ That said, it’s more than a little bit disappointing that the artillerist doesn’t get the spell with the word missile in it. \$\endgroup\$ Aug 19, 2021 at 4:32
  • \$\begingroup\$ Yeah, seriously. I won't plow old ground here, but this is another example of the artillerist being just far enough off the concept I have in my head that it chafes. Maybe RPG.SE needs a sister site called "stackcomplains" where gripes like this are the only thing that's on-topic. \$\endgroup\$
    – screamline
    Aug 19, 2021 at 16:20

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