(Int; Trained Only)

You are educated in a field of study and can answer both simple and complex questions. Like the Craft, Perform, and Profession skills, Knowledge actually encompasses a number of different specialties. Below are listed typical fields of study.

Check: Answering a question within your field of study has a DC of 10 (for really easy questions), 15 (for basic questions), or 20 to 30 (for really tough questions).

You can use this skill to identify monsters and their special powers or vulnerabilities. In general, the DC of such a check equals 10 + the monster's CR. For common monsters, such as goblins, the DC of this check equals 5 + the monster's CR. For particularly rare monsters, such as the tarrasque, the DC of this check equals 15 + the monster's CR, or more. A successful check allows you to remember a bit of useful information about that monster. For every 5 points by which your check result exceeds the DC, you recall another piece of useful information. Many of the Knowledge skills have specific uses as noted on Table: Knowledge Skill DCs.

Table: Knowledge Skill DCs
TaskKnowledge SkillDC
Identify auras while using detect magicArcana15 + spell level
Identify a spell effect that is in placeArcana20 + spell level
Identify materials manufactured by magicArcana20 + spell level
Identify a spell that just targeted youArcana25 + spell level
Identify the spells cast using a specific material componentArcana20
Identify underground hazardDungeoneering15 + hazard's CR
Identify mineral, stone, or metalDungeoneering10
Determine slopeDungeoneering15
Determine depth undergroundDungeoneering20
Identify dangerous constructionEngineering10
Determine a structure's style or ageEngineering15
Determine a structure's weaknessEngineering20
Identify a creature's ethnicity or accentGeography10
Recognize regional terrain featuresGeography15
Know location of nearest community or noteworthy siteGeography20
Know recent or historically significant eventHistory10
Determine approximate date of a specific eventHistory15
Know obscure or ancient historical eventHistory20
Know local laws, rulers, and popular locationsLocal10
Know a common rumor or local traditionLocal15
Know hidden organizations, rulers, and locationsLocal20
Identify natural hazardNature15 + hazard's CR
Identify a common plant or animalNature10
Identify unnatural weather phenomenonNature15
Determine artificial nature of featureNature20
Know current rulers and their symbolsNobility10
Know proper etiquetteNobility15
Know line of successionNobility20
Know the names of the planesPlanes10
Recognize current planePlanes15
Identify a creature's planar originPlanes20
Recognize a common deity's symbol or clergyReligion10
Know common mythology and tenetsReligion15
Recognize an obscure deity's symbol or clergyReligion20
Identify a monster's abilities and weaknessesVaries10 + monster's CR

Action: Usually none. In most cases, a Knowledge check doesn't take an action (but see “Untrained,” below).

Try Again: No. The check represents what you know, and thinking about a topic a second time doesn't let you know something that you never learned in the first place.

Untrained: You cannot make an untrained Knowledge check with a DC higher than 10. If you have access to an extensive library that covers a specific skill, this limit is removed. The time to make checks using a library, however, increases to 1d4 hours. Particularly complete libraries might even grant a bonus on Knowledge checks in the fields that they cover.