[RPG] Will I know if the attack is modified by monster vulnerability, resistance or immunity


In Dungeons and Dragons 5th edition, when my character successfully hits a monster in combat, does the GM have to tell me whether the attack deals the usual amount of damage or not? If the monster has vulnerability, resistance or immunity to the type of damage I am dealing, is the GM obligated to tell me?

Best Answer

The DM is obliged to tell you

This obligation arises from the How to Play section on p.6 of the PHB, that is, the most fundamental rule in the book:

3. The DM narrates the results of the adventurers’ actions.

The player has scored a hit for a known amount of damage (from the dice they rolled and their modifiers): "the results of the adventurers’ actions" is different if the monster has vulnerability, resistance or immunity to the damage than if they do not and the DM is obliged to communicate that difference to the player.

How that communication takes place is up to the individual table DM: some will straight out tell the player's that the monster is vulnerable/resistant/immune and others will describe the effects ("Your blow does more/less/no damage than you expected" smart players will twig pretty quick). However they do it, it is important that they do do it.

Why it is important is simple: the sole source of information about the world comes from the DM. The players need that information so that they can make informed decisions (like switching to a different damage type). This is not to say that the players should get information their character's don't know or can't perceive, however, following a successful attack the effects of the hit are neither.