What skill gives knowledge of undead?

Question

In a recent D&D 5e session, the issue came up where the party wanted to identify an undead creature, along with its strengths and weaknesses.

The party Wizard wanted to use the skill he was proficient in (Intelligence (Arcana)) since according to the PHB it covers "... the planes of existence, and the inhabitants of those planes".

The party Paladin wanted to identify it using the skill he was proficient in (Intelligence (Religion)). Although undead are not explicitly mentioned in the description of that skill, his logic was that learning about undead and their strengths and weaknesses would make up a significant part of his religious training as a Paladin.

Is there a (RAW) explanation of which skill would give a player insight into the nature of undead enemies? Is it either of the mentioned skills, or more based on a character's background learning, as decided by the GM?

Answer 1

DMG Page 239:

Often, players ask whether they can apply a skill proficiency to an ability check. If a player can provide a good justification for why a character's training and aptitude in a skill should apply to the check, go ahead and allow it, rewarding the player's creative thinking.

Since the players have justified using both Arcana and Religion, then let them use either. Both skills are perfectly good ways to have acquired the knowledge.

Answer 2

I'm very lenient on how skills can be used, provided the players have a good explanation for them, and tend to tailor the DCs based on their explanations. One of the most fun things I've experienced as a DM is trying to explain how a natural 20 on a wacky skill check resulted in anything useful.

To your specific example, I would give the arcane check an answer more in line with how they are created, whether they could serve a master or be controlled, and the like, as that is more arcane knowledge. (e.g. you believe this is a mummy, created by a very powerful spell)

To the religion check, I would mention that divine power can destroy or turn undead, that undead are typically considered evil. I consider knowledge of undead to fall into this skill, so I would make it an easier check to get the same info as the arcane check.

In general, however, I use results from these kinds of "knowledge" checks to further the plot and story of the campaign, sneaking in tidbits of information that might be known by one player or the other to further set up the campaign.

As a recent example, I decided that even without rolls, most of the characters in the party, knew what Gricks were, because they were a party of dwarves and an orc that used to be part of a mining crew. Additionally, when the druid made a successful nature check, I allowed him to identify the Grick Alpha and get a rough idea of his abilities vs the regular Gricks. I also imparted on the orc player that they are typically used as an easy means of disposing of the sick and the dead among orc tribes, to set up that they were near an orc encampment.

Answer 3

As stated in the SRD Religion doesn't give the identification of undead in its description:

Religion. Your Intelligence (Religion) check measures your ability to recall lore about deities, rites and prayers, religious hierarchies, holy symbols, and the practices of secret cults

Monster identification was seemingly removed entirely to simple intelligence checks with the possible exception of the old Knowledge Planes which was rolled into Arcana. I personally allow characters to add their PB to their int checks depending on the given situation (Paladin of Pholtus would definitely know about undead as an example). I am much stricter on what a given background/class/culture would be trained in or have experience with however.

I have to say that not all Paladins would necessarily be trained to recognize undead. Example: Oath of the Ancients may or may not be, given that they are Nature based and of course whether there is enough undead in the region of their training that could warrant that knowledge. This is up to individual DMs to decide of course.

Bottom line is that it should fit your game and style of play as this is somewhat outside the realm of the explicit rules.