What should players know about monsters?

[TinyBlooper]

How do you determine how much to tell players about a creature they're fighting? For example, if your players are fighting a (flips to a random page of the MM) Bone Devil, I assume you wouldn't just tell them that its immune to fire and poison and has magic resistance. Do they make an arcana check? Religion? I wasn't able to find a specific rule on the subject.

[Sigreid]

A knowledge check for me gives them a name, creature type and maybe some clues wrapped up in a story. Nothing gets the a stat block or stats.

[MrStabby]

It isn't an easy question.

It is easy to say that a bone devil might be rare, PCs have no reason to know about them. How about sages? acolytes? Some backstories? How about knowledge checks?

What about knowing that in general fiends are immune to fire and that everything interesting is immune to poison?


On the other hand there is a certain expectation that a fantasy world will match some expectations. "the party advances till late afternoon where you come across a lone goblin on a bridge brandishing a spear" - and the part runs away being unprepared to metagame to know that goblins are quite weak. Or doesn't thing that a venomous snake will just do some poison damage rather than just kill outright (or at least risk doing so).


A mixture of shaking things up and using new stuff coupled with giving out a decent amount of information (ideally tied to PC backgrounds on in game actions) should sort most problems. There isn't really a single simple solution though.

[Thrudd]

Ideally, they should know nothing and you should tell them nothing. They find out things by interacting with it. You might allow a check of an appropriate lore skill to give them a little information. Not "arcana", I think, that is for identifying spells and workings of magic. Monster information would be nature or religion or maybe even history, depending on what type of monster it is. Of course, it depends on your world, as well. If you decide it to be inappropriate for the characters to know anything about a monster, you can just say that nobody has any information about it, regardless of any checks.

[Typhon]

Depends. A cleric or paladin may have some scriptures that relate to demons they could reference. Wizards have books to reference and bards may just know something. Warlocks, depending on pact, may know something or know where to possibly look.

So it would come down to checks. Religion, arcana, or even just intelligence. Set 10 for duh level, 15 for basic things, 20 for more specific, 25 for pretty specific, and 30 for you could almost find it's real name.

[Naanomi]

Depends a lot on the setting... trolls are incredibly common in one place: knowing about them and how to drive them off is 'peasant survival 101'; while another place may have never heard of them as they are almost extinct ancient horrors from a previous age

[mgshamster]

I do a knowledge check.

However, there's a caveat with that. The lower level they are, the less information they get. At level 1, a NAT 20 will get them a name and ecological data. Maybe something about a weakness or strength.

By level 10, they get practically everything on an average roll, unless it was particularly unique or special.

Basically, I play it by ear with lower levels being less informative.

[Bahamut7]

Depends a lot on the setting... trolls are incredibly common in one place: knowing about them and how to drive them off is 'peasant survival 101'; while another place may have never heard of them as they are almost extinct ancient horrors from a previous age

This is typically the best way to approach it. As well as character class and background. Paladins and Clerics may gleam more knowledge about fiends and Undead than the Wizard, but the Wizard may know more about other creatures. I could see Bards knowing a bit more about Fey related creatures because of their nature to tell stories.

I would leave it down to the player to justify how much they could gleam from an appropriate knowledge check (Arcana, History, and Religion could apply to some or most). Depending on the region, survival or nature can also apply. For example, a Ranger could justify a survival check with creatures that are native to their neck of the woods. Any class can be worked appropriately, but it's up to you as the DM how far that can and will go. I also like Typhoon's Set 10 for duh level, 15 for basic things, 20 for more specific, 25 for pretty specific, and 30 for you could almost find it's real name as a good basis.

Also, don't be afraid to leak out common misconception type knowledge. For example with the Bone Devil, one might assume that the creatures tough skin or exoskeleton may grant it resistance to even magical slashing or piercing weapons (not true) but a fair assumption.

[busterswd]

I Dresden Files this; that is to say, if they can justify in their backstory why they would know about a monster, I'll give more helpful information. I'll also try to make what they're given ring true to their background.

A barbarian who's been fighting undead for a while encounters a vampire, and rolls well:

"You've heard they're notoriously hard to injure, and injuries don't seem to stick. On top of that, their foes have been known to change sides mid fight and aid them. They've never been spotted during the day."

Same barbarian who rolls poorly:

"They're tough to kill, and even the braver warriors in your clan who've fought many of the undead before tend to fear them."

Wizard who rolls well:

"While resistant to injury, radiant energy has been documented in many cases to sublimate their flesh. They've been known to mimic enchantment and necromantic magic in order to subdue and drain their prey of life force."

[Bahamut7]

I Dresden Files this; that is to say, if they can justify in their backstory why they would know about a monster, I'll give more helpful information. I'll also try to make what they're given ring true to their background.

A barbarian who's been fighting undead for a while encounters a vampire, and rolls well:

"You've heard they're notoriously hard to injure, and injuries don't seem to stick. On top of that, their foes have been known to change sides mid fight and aid them. They've never been spotted during the day."

Same barbarian who rolls poorly:

"They're tough to kill, and even the braver warriors in your clan who've fought many of the undead before tend to fear them."

Wizard who rolls well:

"While resistant to injury, radiant energy has been documented in many cases to sublimate their flesh. They've been known to mimic enchantment and necromantic magic in order to subdue and drain their prey of life force."

This is what I would want from any DM on knowledge checks.

[Citan]

Hi!
Honestly, it's a somewhat hard question to answer without specific context.

What I usually do is to "filter down" what one can know about a creature by following this process.

1. Is the creature common in the setting?
2. Is the character any knowledgeable about one kind of creatures? Paladins and Cleric are susceptible to know about undead, celestials and demons, Druids about elementals and fey, Wizards about aberrations etc.

These are the main questions.
If the creature is really common, it's very probable than any people have basic knowledge about its moves and strengths/weakness (such as undead hordes around the world -> anyone knows it's vulnerable to fire for example -giving a random example here-)

If, in addition to this, the character has a knowledge of this kind of creature because of background or class, he may have a general idea of its characteristic (broad estimation of HP, weakness, etc)...

To try and theorize this, let's try the following.
There be an ordering of information (0 being the basic description any DM should give imo).
0. Visible information (worn equipment for example: weapons, armor, focus, relics).

1. Very broad information ("seems strong" > STR, "seems very sturdy" > high AC or high HP, "seems agile" > maybe very fast or very high DEX).

2. Creature type and broad CR evaluation ("you have a feeling it's a worthy opponent", "seeing it makes your spine shivers")

3. More precise information: HP estimation ("less than 20", "more than you"), main strength if visible (very high STR = "powerful opponent" for example), main weakness but only if visible or common knowledge (confer zombie example).

4. 1-2 max precise informations about general characteristics (one immunity/vulnerability, AC, speed, HP, senses, best save).

5. One only very accurate tip (worst save, special ability like Multi-Attack, one of prepared spells).

Then, which "level" would party access?
Creature "rarity" in setting: legendary (-1), rare (0), occasional (+1), common (+2).
Party already encountered and fought creature (or got precise information about it any other way, like spending downtime looking for tips): +1
So with this, you can get good enough information "without doing anything", but it's still broad enough to keep mystery and challenge imo.

THEN...
Any character who has good reason to get any knowledge about the specific creature (backstory, class, skill, background) may roll a related check (Arcana, Religion, maybe History). On 15+, he gets all level 3 information and ONE level 4 information. On 20+, he gets one additional level 4 information. On 25+ he gets also one level 5 information. On 30+, you may even, maybe, consider dropping a key information. Or not. ^^

Other characters may or not try Investigation, Perception or other checks but will never get anything more than a level 3 information.

Obviously, each character gets one try max.

In short, main idea is to give the party...
1. Things that they could probably guess or deduce anyways from the description you gave to them.
2. Just enough information so they know at least if this is a creature they could challenge or would better avoid.
3. Enough information to design basic tactic.
4. One or two tips that avoid them wasting actions (by using a DEX-saved spell on a very agile creature for example, or trying to attack it when it has 19+ AC).
5. A key information that help them optimize or turn the tide (weakness to INT spells, usually keeps a given spell prepared, etc).

You're welcome to adapt, this is something made more on less on the fly with broad strokes, with some arbitrary choices you may dislike (like limiting information whatever happens).
It may be a helpful tool for some, just a clumsy bother to others... :)

EDIT: oh and, obviously, even when giving precise information, don't give it bland like "it has 14 AC". Fluff it, like in examples given by above posters.

I do a knowledge check.

However, there's a caveat with that. The lower level they are, the less information they get. At level 1, a NAT 20 will get them a name and ecological data. Maybe something about a weakness or strength.

By level 10, they get practically everything on an average roll, unless it was particularly unique or special.

Basically, I play it by ear with lower levels being less informative.
True that, it's something to consider... Obviously starting adventurers will have few general knowledge compared to high level ones... Dang, it's hard trying to set up a "system".
Following gut may be the simplest way after all... ^^

[Kane0]

It's times like these you need the rule of three:

Is the monster:
A) Uncommon / infamous
B) Rare / acknowledged in lore
C) Unique / obscure

Depending on location, the vast majority of people can be reasonably expected to know about category A and be able to identify them and their special traits.
Those particularly educated or involved with the subject matter will also know B and be able to specify any notable abilities.
Category C is the one where people will have to do some serious research, and only expoerts will know much about them.

For those DMs that prefer to use Intelligence checks in order to identify monsters then DCs of 15, 20 and 25 are about fair. Arcana, Nature and Religion would be the most common ones for generic monsters whereas History will bring up notable individuals or events and investigation can help search for relevent information (such as in a library or locating a specialist in the field)
You can provide advantage or disadvantage if the character would have some sort of edge (like living in the same habitat or specialising in that creature type, etc) or issue (deliberately misinformed, no exposure to creature type, etc)

The DM is free to dispense as much information as they see fit, and it varies depending on the table and type of game. A horror game would be no good if you tell everyone exactly what the horrible monster can and cannot do, nor will a beer and pretzels game be much fun if you never even tell your players what kind of attacks to avoid. An RP heavy group may hate you telling them the mechanical stats of a creature and those that prefer as much concrete information as possible may find constant fluffy descriptions annoying.

[MarkVIIIMarc]

Like said above, decide how rare the creature is and have a roll.

I live in the American Midwest. Only a handful of times in my life have I seen a hippo. All at zoo's. If we had to fight one though I would have a fair idea its intelligence is 4 or 5 ish, its strength and A/C are unreal and I don't want it to chomp or step on me.

Adventurers should be at least as familiar with all but the very arcane foes. In taverns they'll share stories, in training they'll be instructed etc.

[Naanomi]

Adventurers should be at least as familiar with all but the very arcane foes. In taverns they'll share stories, in training they'll be instructed etc.
Though it is always fun to do a 'you were transported to fantasy Asia (or whatever), far from the fantasy Europe monsters you are familiar with!' Adventure

[Kane0]

Imagine them fighting an 'ogre mage' only to find much later it was actually an 'oni'

[Pex]

Ideally, they should know nothing and you should tell them nothing. They find out things by interacting with it. You might allow a check of an appropriate lore skill to give them a little information. Not "arcana", I think, that is for identifying spells and workings of magic. Monster information would be nature or religion or maybe even history, depending on what type of monster it is. Of course, it depends on your world, as well. If you decide it to be inappropriate for the characters to know anything about a monster, you can just say that nobody has any information about it, regardless of any checks.

That is not ideal at all. It's not an abomination for players to know stuff. There's a reverse metagame. There are things the character knows the players do not, and that could include the details of the monsters that inhabit the world. PCs are not completely ignorant.

One solution is use the benchmarks of easy, medium, hard, etc. (DC 10, 15, 20 and so on). The player makes a knowledge check. The type of knowledge is based on the monster. Magical beasts are likely Arcane. Planar beings would be Arcane or Religion. Naturally occurring is Nature. Undead could be Religion. Based on the total consider the monster in question and apply its abilities to how easy or hard it is know the information using your judgment. Special monsters would need higher DCs. For example, a beholder or lich would give no info on anything less than 20. Iconic info is easy. DC 10 lets a PC know to use fire against a troll, but a DC 15 reminds them acid works just as well.

When you're preparing your adventure you might want to take the extra time to create DC knowledge tables for the monsters you are using especially if you know at least one player wants to make Knowledge checks as part of strategy. If players aren't asking that often you can just wing it.

[Ngagn]

It's times like these you need the rule of three:

Is the monster:
A) Uncommon / infamous
B) Rare / acknowledged in lore
C) Unique / obscure

Depending on location, the vast majority of people can be reasonably expected to know about category A and be able to identify them and their special traits.
Those particularly educated or involved with the subject matter will also know B and be able to specify any notable abilities.
Category C is the one where people will have to do some serious research, and only expoerts will know much about them.

For those DMs that prefer to use Intelligence checks in order to identify monsters then DCs of 15, 20 and 25 are about fair. Arcana, Nature and Religion would be the most common ones for generic monsters whereas History will bring up notable individuals or events and investigation can help search for relevent information (such as in a library or locating a specialist in the field)
You can provide advantage or disadvantage if the character would have some sort of edge (like living in the same habitat or specialising in that creature type, etc) or issue (deliberately misinformed, no exposure to creature type, etc)

The DM is free to dispense as much information as they see fit, and it varies depending on the table and type of game. A horror game would be no good if you tell everyone exactly what the horrible monster can and cannot do, nor will a beer and pretzels game be much fun if you never even tell your players what kind of attacks to avoid. An RP heavy group may hate you telling them the mechanical stats of a creature and those that prefer as much concrete information as possible may find constant fluffy descriptions annoying.

This! It all depends on the nature and rarity of the monster

[DMThac0]

I have to agree with Kane0 as well, that's a fairly succinct summary of how character knowledge would play out.

In one session I had recently I described to a player: "You see in the cage a large grey beast, it's hide covering it's body almost like armor, and a large horn protrudes from it's face". Now to you and I, and the player, this is most likely a rhinoceros, but choosing the words carefully I created what the character would believe to be a fantastic strange animal they've never seen. Sure they could have simply called out that it's a rhino, but by creating the scene with well chosen words it implied that the player didn't have that knowledge. I didn't make them roll a knowledge check, I didn't even wait for them to ask what they saw, I simply took the initiative to create the scene.

In a session I run with my kids and 2 veteran players I had to describe Gnolls in such a way that created the same implied lack of knowledge. "You see this strange dog like creature walking on two legs walk into the clearing, it looks kind of like a mix of a human and the hyena's from Lion King, and it's carrying an axe in it's hands. With one look from the creature at you it snarls and quickly disappears into the trees." One of my vets mouthed to me "Gnoll" as I was describing the situation but kept quiet beyond that. He had picked up on the idea that this was something new and strange. Again I didn't make anyone roll a knowledge check, until one of my kids asked if they knew what it was, at that time I asked for a roll. When they gave me the number I replied with, "You've never seen a creature like this before, but you remember one of your ranger buddies talking about a Gnoll and how they hunted in packs in the forest."

Your players know what you tell them, you choose what to tell them. What makes it interesting is how you tell them.

[NNescio]

I let everyone with the relevant Knowledge skill roll for it, giving increasing amount of information (resistances, immunities, special traits and abilities, known combat tactics) the higher they roll (basically tiered DCs). Of course rarer monsters and more esoteric information would require higher rolls. No action required, just roll (even out of turn) when the player sees the monster for the first time. For less important stuff I sometimes just use their passive Knowledge (take 10).

(Anybody with a result lower than a 5 would instead be given blatantly false information that no PC would be fooled by OOC.)

I generally don't allow nonproficient checks since it tends to bog down the game.

And of course, anyone with the necessary backstory get a free pass on the necessary information. Forest Rangers and Druids don't need to roll to know most things about bears or some other woodland creature.

[Logosloki]

If I believe the characters would reasonably know what the creature is, I announce it as such (Kobolds pour out from the crevices in the tunnel wall). If I believe that the characters would not reasonably know a monster off hand I give a general description as part of dressing the scene (The ground itself rents apart, a snapping armoured head rushes up from the gap, powerful forearms driving it above ground) to give players an indication that if they wish to roll a few checks they are welcome to.

Knowledge checks on creatures for me represent remembered trivia - they heard about it from some other adventurers, an old tome comes to mind, a bed time story from your nan, a song or poem or bawdy rhyme, etc. I usually set knowledge checks low (5 for name, 10 for general description and what to generally expect, 15 for specifics or any nasty good-natured surprises I might have put in, get a 20 and I reveal the monster card)

[ClearlyTough69]

I let them use Knowledge checks; the type of check depends on the creature:


Arcana: Aberrations, Constructs, Elementals, Monstrosities
Religion: Celestials, Fiends and Undead
Nature: Beasts, Fey, Oozes, Plants
History: Dragons, Giants and Humanoids


Make the appropriate check against DC = 13 + CR (for CRs lower than 1, turn them into negative numbers, so CR 1/2 becomes 0, CR 1/8 becomes -2). For creatures with legendary actions, use half the CR: these are creatures of legend, and people tell stories about them so they're part of the general consciousness!

Meeting the DC lets you identify the creature correctly. For every point by which you exceed the DC, you recall one fact from the creature's description or you can compare a statistic of that creature to one you already know about (eg is it stronger than a warhorse? does it have more hit points than a brown bear? answers can be yes, no, about the same).


If you can identify the lesser form of a creature, but not the greater form, then you might make a mistake, eg if your Religion check result does not tell you that you are facing a Mummy Lord, but is good enough to identify a Mummy, you will think you are facing a Mummy and might recall facts about that creature. The facts are likely to be right, but you'll probably underestimate your opponent!

[LordVonDerp]

For example, if your players are fighting a (flips to a random page of the MM) Bone Devil, I assume you wouldn't just tell them that its immune to fire and poison and has magic resistance. Do they make an arcana check? Religion? I wasn't able to find a specific rule on the subject.
Depends on how the creature is described.
We can find a basic description and picture for the bone devil here:
http://dnd.wizards.com/articles/features/excerpt-bone-devil

From that the characters can tell the following without needing any checks
-The creature is skeletal in nature
-It smells of death and decay
-It has sharp claws
-It has a scorpion-like tail

So from that players should know (again, without the need for any check)
- it's immune to poison
- it has a poison attack

Other than that it depends on if the characters know it's a devil.