using knowledge to ID monsters

[bjoern]

Hypothetical situation here.
A guy with knowledge arcana 8 ranks
And knowledge the planes 3 ranks
Sees a monster and wants to try to ID it. Should the DM just know what his check modifiers are and roll behind the screen or should the player pick a skill randomly and try it? Let's just say that the monster is a displacer beast. The character says that he wants to try to use knowledge the planes to ID it. Rolls a 19. DM says he has no idea what it is (used wrong knowledge skill)
Or should the DM ask him to make a Knowledge arcana check? But now, even if the player fails miserably he knows that its either a dragon, magical beast, or construct.

[Agincourt]

Hypothetical situation here.
A guy with knowledge arcana 8 ranks
And knowledge the planes 3 ranks
Sees a monster and wants to try to ID it. Should the DM just know what his check modifiers are and roll behind the screen or should the player pick a skill randomly and try it? Let's just say that the monster is a displacer beast. The character says that he wants to try to use knowledge the planes to ID it. Rolls a 19. DM says he has no idea what it is (used wrong knowledge skill)
Or should the DM ask him to make a Knowledge arcana check? But now, even if the player fails miserably he knows that its either a dragon, magical beast, or construct.

Ideally, the DM would make all the knowledge checks for the reason you pointed out. Even complete failure would give the player some information that their character does not know.

However, I find that to not be practical. DMs already need to keep a lot of information at the ready. Adding 11 knowledge check for every PC, plus possibly those of NPC allies or cohorts, is just too much work to expect of a DM. Generally, I find it better to just ask the players not to metagame with the information they should not know.

Using your example, it might be really helpful for the player to know a monster is a construct, but it is not usually helpful to know something is a magical beast and not an aberration. If the PC fails miserably on the knowledge arcana check, it may be a good idea to remind the players that they do not know that this is a construct. If, however, the player just misses the DC on the knowledge arcana check, it's not unreasonable for the DM to say, "you know it's a construct, but you're unable to figure out which type."

[Gildedragon]

Well when players says "I want to ID it" DM ought answer expeditely with "Roll X knowledge to do so"
Baator, the DM ought say that when the monster appears: "A creature (description) pounces upon you, roll knowledge X to identify it"
Speaking of, I need to post that on a pbp...

[jedipotter]

Hypothetical situation here.


For the most part, the player should roll most things like skill checks. So I player would say ''I will roll and use this skill''.

Most players, the types obsessed with knowing things with this type of free roll, will often run through and roll all the knowledge skills they have....

[BowStreetRunner]

In truth, the rules don't explicitly cover how to make a knowledge check. All the rules tell you is which knowledge you need and the DC of the check.

Some DMs prefer to simply ask the player to make a knowledge check against the specific knowledge. "Make a Knowledge: nature check please."
Other DMs will keep track of the players' modifiers and not tell them against which knowledge they are rolling unless they are successful.
Some DMs even go as far as to make the check for the player.

Then there are the Lore entries that appeared beginning with Monster Manual IV, where the information gleaned is presented in a table. Since monsters before MMIV did not have this table, DMs using this convention have to find a way to handle checks for earlier monster entries. (Some players have been working on putting together a Monster Lore Compendium (http://community.wizards.com/forum/previous-editions-general/threads/1074581) for earlier books.)

Another complication that comes into play is how to handle abilities such as an archivist's Dark Knowledge rolls or the rolls that go with the Knowledge Devotion feat. Since the rules are not explicit, some DMs allow players to make a single roll to ID the monster and apply that result to these abilities, and others require a separate roll.

Ultimately, it is up to the individual DM how they want to handle these things.

[Extra Anchovies]

In my opinion, a character with ranks in a Knowledge skill tied to a particular creature type should be able to identify monsters of that type on sight (that is, they would know whenever they were faced with a creature of the type, but not necessarily know what the exact creature is [that's what making the knowledge check is for]), presuming they aren't disguised or using magical alterations. At the very least they should know whether the creature in question falls under their area of expertise (e.g. someone with ranks in Knowledge [Arcana] would be able to, by looking at a creature, tell if it is a construct/dragon/magical beast or if it is not, but would have to actually make the check to determine the exact nature of the creature).

[HighWater]

I used to have players roll for each knowledge skill individually, but abandoned it because there's some overlap in knowledge skills. It basically resulted in players trying other knowledge skills in the hopes they'd roll a 20 to offset the 1 they just rolled (no criticals on skills, but 19 points is a lot of difference).

A new (for me) method I introduced one or two games back was letting the players make one knowledge roll each, then tell me the modifiers they have on each knowledge skill. For example:

Player X has Knowledge Religion and Knowledge Arcana and wants to roll a knowledge check. They roll a d20, and roll a 12. They then tell me "I have 6 points in Arcana for 18 and 10 in Religion for 22, what do I know?"

That way I don't spoil immediately which roll is important. This is less of a problem for monsters, but when it comes to "mysterious setting stuff" knowing that you DON'T remember a particular sign from your knowledge History can already be a big reveal.

[Extra Anchovies]

I used to have players roll for each knowledge skill individually, but abandoned it because there's some overlap in knowledge skills. It basically resulted in players trying other knowledge skills in the hopes they'd roll a 20 to offset the 1 they just rolled (no criticals on skills, but 19 points is a lot of difference).

A new (for me) method I introduced one or two games back was letting the players make one knowledge roll each, then tell me the modifiers they have on each knowledge skill. For example:

Player X has Knowledge Religion and Knowledge Arcana and wants to roll a knowledge check. They roll a d20, and roll a 12. They then tell me "I have 6 points in Arcana for 18 and 10 in Religion for 22, what do I know?"

That way I don't spoil immediately which roll is important. This is less of a problem for monsters, but when it comes to "mysterious setting stuff" knowing that you DON'T remember a particular sign from your knowledge History can already be a big reveal.

This is a really great idea, actually. Probably going to start using it. After all, IRL it's sometimes a lot harder to recall why you know something than it is to recall the fact itself.

[VoxRationis]

In my opinion, a character with ranks in a Knowledge skill tied to a particular creature type should be able to identify monsters of that type on sight (that is, they would know whenever they were faced with a creature of the type, but not necessarily know what the exact creature is [that's what making the knowledge check is for]), presuming they aren't disguised or using magical alterations. At the very least they should know whether the creature in question falls under their area of expertise (e.g. someone with ranks in Knowledge [Arcana] would be able to, by looking at a creature, tell if it is a construct/dragon/magical beast or if it is not, but would have to actually make the check to determine the exact nature of the creature).

That said, certain constructs are not superficially dissimilar from certain undead, for example. Belkers could easily be confused for incorporeal undead even by those with 1 rank in Knowledge (religion) or (the planes). The types are usually based on concepts or internal "essence" rather than purely physical characteristics; a monster might be a "dragon" when a monster visually similar to it was "magical beast," for reasons not apparent until you know the name of the monster and some of the description text from its Monster Manual entry.

[Duke of Urrel]

As a DM, I distinguish two kinds of Knowledge checks: granted checks and elective checks.

A granted Knowledge check is one that I allow a PC to make when I believe a character may know something even when the character's player does not. In order to keep the outcome of a granted Knowledge check secret, I usually let this check take 10 by default (that is, whenever the rules allow it), and I do not inform the PC that I have granted a Knowledge check unless it succeeds. If it's necessary to roll this check (because of threats or distractions), I have every player roll 1d20 and add Knowledge modifiers only to those checks that count. (Presumably not every PC has Knowledge in every field.) This method insures that a failed check never gives away any information. Of course, this method also requires the DM to keep track of every PC's Knowledge skill modifiers.

An elective Knowledge check is one that a player chooses to make for his or her PC, in order to answer a question that the player has. This Knowledge check is always made by the PC, but it may take 10, too, according to the rules. To avoid predictability and meta-game deductions based on Knowledge check scores, I believe the DM has the power and even the responsibility to modify the standard Knowledge DCs that appear in the Player's Handbook, because it is the DM's task to create the world's ecology and therefore also the DM's task to determine how rare or how common any kind of creature is. The following three paragraphs explain what I do, particularly in regard to identifying monsters.

1. The general rule for identifying monsters is that the Knowledge DC of this check is 10 plus the monster’s Hit Dice. If a creature belongs to an uncommon, rare, or obscure species, I may modify this DC by adding +5, +10, or +20, respectively. On the other hand, if a creature belongs to a well-known species, I may add only one-half or one-quarter of the creature’s Hit Dice to the DC.

2. I do not allow Knowledge of any kind to enable you to see through a disguise or an illusion or to guess the natural form of a creature that has polymorphed itself into a creature of a different species. The best that your Knowledge can do is tell you which species this creature presently resembles. I make an exception for creatures of the Shapechanger subtype that can assume no more than three different forms, but the Knowledge DC to identify a Shapechanger of this kind adds +15, unless you actually see it change, in which case the DC is normal.

3. On the other hand, if you have at least one rank of Knowledge skill in a particular field that enables you to recognize undisguised creatures of a certain type on sight, I always allow you to identify this creature by type as soon as you see it. This works like a granted Knowledge check that automatically succeeds. For example, if you have at least one point of Local Knowledge and you see an undisguised Humanoid, you immediately identify it as such, and if you have at least one point of Knowledge of Nature and you see an undisguised Vermin, you immediately identify it as such.

Finally, what happens when a question falls into two or more fields of Knowledge at once? When this happens, I don't grant a PC two or more Knowledge checks. Instead, I allow the PC to make only one Knowledge check in only one field. This field is always the one in which the PC has the most Knowledge, so that this Knowledge check is always the one most likely to succeed.

Postscript: These house rules differ from the ones I proposed in an earlier thread. The Playground often convinces me to change my mind!

[Hazrond]

Most players, the types obsessed with knowing things with this type of free roll, will often run through and roll all the knowledge skills they have....

Do us a favor please and DON'T start this again

[jedipotter]

Do us a favor please and DON'T start this again

Start? It was never finished...it's a never ending story. "Tharks did not start this, but By Isis, we will finish it!'' Roll DC 30 to get the refrence....lol.

[Hazrond]

Start? It was never finished...it's a never ending story. "Tharks did not start this, but By Isis, we will finish it!'' Roll DC 30 to get the refrence....lol.

Dangit, I failed, I'll need more knowledge ranks next level

[DarkWhisper]

Hypothetical situation here.
A guy with knowledge arcana 8 ranks
And knowledge the planes 3 ranks
Sees a monster and wants to try to ID it.

PC: "Remembering Monsters of the World - Illustrated Special Edition, I try to identify the creature."
DM: *rolls behind screen* "What are your knowledge check bonuses ?"
PC: "Arcana +8, the Planes +3"
DM: *adds the +8 from Knowledge (Arcana) to the roll* "The creature ambling along the edge of the chasm is almost certainly a Displacer Beast, which are famous (and feared) for..." [continues to give one piece of useful knowledge for ever 5 points the check has beaten the DC]

At least, that's how I do it.