When creating a monster, on DMG p. 274 I am instructed to "Read down the Damage/Round column... until you find your monster's damage output per round."
So how do I figure that? Is it just the damage output of the creature's attack(s)? What if an attack could hit multiple targets, like the breath weapon of a dragon?
On p.277, under Step 11. Damage, we get close to defining this:
It doesn't matter how this damage is apportioned or distributed; for example, a monster might deal the damage every round with a single attack, or the damage could be split among multiple attacks against one ore more foes.
Okay, but how do I figure the damage for a breath weapon? It's going to be potentially very large variance depending on whether I think it's hitting one character or several.