[RPG] How to handle simultaneous damage when one type is absorbed and not the other

damagedamage-typesdnd-5emonsterssimultaneous-effects

Say a wizard sees something a group of large figures lumbering towards him/her. The wizard is overly paranoid about being outnumbered so they drop a Meteor Swarm spell on them. However, it turns out the group were all Iron Golems. According to their stat block they will absorb the fire damage from the meteor swarm, but take the bludgeoning damage from the spell as HP loss.

How do you resolve the damage taken? If you apply the fire damage first and they are at full HP they won't heal from it, then the bludgeoning damage will hurt them after that.

If you apply them simultaneously then I'm still not sure. I can't decide if simultaneous means subtracting the fire damage from the bludgeoning damage, or if you apply each based upon the current HP of each Iron Golem then resolve the difference. eg. If they are at full HP they'd get +0 from the fire damage and -20d6 from the bludgeoning damage. Adding them together then you end up with 20d6 damage.

Best Answer

Xanathar's Guide to Everything has guidelines for simultaneous effects; the person whose turn it is determines the order of simultaneous events

The meteor swarm spell states:

[...] A creature takes 20d6 fire damage and 20d6 bludgeoning damage on a failed save, or half as much damage on a successful one [...]

It gives no indication of these happening at different times, and so we will assume that they happen simultaneously. In this case we can look to Xanathar's which states:

Most effects in the game happen in succession, following an order set by the rules or the DM. In rare cases, effects can happen at the same time, especially at the start or end of a creature’s turn. If two or more things happen at the same time on a character or monster’s turn, the person at the game table — whether player or DM — who controls that creature decides the order in which those things happen. For example, if two effects occur at the end of a player character’s turn, the player decides which of the two effects happens first.

In the case here we have two effects (fire damage and bludgeoning damage) happening at the same time. It is (presumably) currently the Wizard's turn and thus they get to determine the order of any simultaneous events, this means that they (presumably) would choose to have the fire damage inflicted first and then the bludgeoning damage afterwards.