At 9th level, the Artillerist gains the Explosive Cannon feature:

  • The cannon's damage rolls all increase by 1d8.
  • As an action, you can command the cannon to detonate [...] dealing 3d8 force damage [...].

This is worded kinda wonky, and I see arguments online about whether the 3d8 detonation damage is increased to 4d8 or not (is the 1d8 already included). RAW, it appears that it should, since usually text would make it explicit if it was already included, as seen in the Bugbear stat block:

  • Brute. A melee weapon deals one extra die of its damage when the bugbear hits with it (included in the attack).

So which is it, is 3d8 a damage roll that is increased by 1d8, or is it just 3d8, period?


1 Answer 1


Rules as written

Rules as written, it does 4d8.

As you noted, the description of Explosive Cannon says, without qualification:

The cannon’s damage rolls all increase by 1d8.

The next bullet says (emphasis added):

As an action, you can command the cannon to detonate if you are within 60 feet of it. Doing so destroys the cannon and forces each creature within 20 feet of it to make a Dexterity saving throw against your spell save DC, taking 3d8 force damage on a failed save or half as much damage on a successful one.

Per the first bullet, the 3d8 becomes 4d8.

The writers could have easily added a clarifying clause, but they didn't. If there is any clarifying or edifying statement, tweet, errata or other clue, I couldn't find it.

Rules as intended

Rules as intended? Perhaps the 1d8 is included in the 3d8; after all, both the Flamethrower and Force Ballista cannons do 2d8, so it makes some sense that that 3d8 is the base 2d8, plus the 1d8. But we don't know, because that's not what the rules say.

A DM can reasonably rule the other way

A DM can very reasonably rule that the exploding cannon does only the 3d8, but again, that's not what the language of the rules say.

Is it overpowered?

Allowing the artificer the 4d8 does not seem to be overly overpowered.

At most, it allows an extra 1d8 of damage every two rounds, starting at 9th level, and an extra 2d8 of damage every 3 rounds, starting at 15th level, at the cost of a spell slot for each cannon, and those affected get a dex save. True, in some situations, if the artificer might be able to get a number of opponents within the 20-foot range of the exploding cannon, but that is situational. All combined, that extra 1d8 does not significantly overpower the explosive cannon, especially compared to other options at those levels.


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