House Rules: Skills - Knowledge

< House Rules: Skills

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.

  • Arcana (ancient mysteries, magic traditions, arcane symbols, constructs, dragons, magical beasts); Although robots are constructs, Knowledge (arcana) cannot be used to identify robots or their abilities and weaknesses.
  • Dungeoneering (aberrations, caverns, oozes, spelunking)
  • Engineering (buildings, aqueducts, bridges, fortifications); This is the most important skill with regard to technological subjects. Knowledge (engineering) can be used to identify a robot’s abilities and weaknesses. Knowledge (engineering) is also used to identify and understand unknown technological objects in a similar manner to how Spellcraft is used to identify the properties of a magic item. The DC to correctly identify and understand an unknown technological object is equal to the object’s Craft DC. An object with a Craft DC of 15 or less can be automatically identified and understood by someone trained in Knowledge (engineering) who also has the Technologist feat.
  • Geography (lands, terrain, climate, people); Used for astronomy.
  • History (wars, colonies, migrations, founding of cities)
  • Local (legends, personalities, inhabitants, laws, customs, traditions, humanoids)
  • Martial
  • Nature (animals, fey, monstrous humanoids, plants, seasons and cycles, weather, vermin)
  • Nobility (lineages, heraldry, personalities, royalty)
  • Planes (the Inner Planes, the Outer Planes, the Astral Plane, the Ethereal Plane, outsiders, planar magic)
  • Psionics
  • Religion (gods and goddesses, mythic history, ecclesiastic tradition, holy symbols, undead)

Action: Attempting to recall knowledge is a smple action.

Retry? 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.


  • Master: When you fail a Knowledge check, you can reroll the check at a –10 penalty. The competence bonus above also applies to saving throws against exceptional, spell-like, or supernatural abilities used by creatures you identify.
  • Legendary: Whenever you attempt a Knowledge check, you can roll twice and take the better result.


General Knowledge (Novice)

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).

Table: Knowledge Skill DC’s

Task Knowledge Skill DC
Identify auras while using detect magic Arcana 15 + spell level
Identify a spell effect that is in place Arcana 20 + spell level
Identify materials manufactured by magic Arcana 20 + spell level
Identify a spell that just targeted you Arcana 25 + spell level
Identify the spells cast using a specific material component Arcana 20
Identify underground hazard Dungeoneering 15 + hazard’s CR
Identify mineral, stone, or metal Dungeoneering 10
Determine slope Dungeoneering 15
Determine depth underground Dungeoneering 20
Identify dangerous construction Engineering 10
Determine a structure’s style or age Engineering 15
Determine a structure’s weakness Engineering 20
Identify a creature’s ethnicity or accent Geography 10
Recognize regional terrain features Geography 15
Know location of nearest community or noteworthy site Geography 20
Know recent or historically significant event History 10
Determine approximate date of a specific event History 15
Know obscure or ancient historical event History 20
Know local laws, rulers, and popular locations Local 10
Know a common rumor or local tradition Local 15
Know hidden organizations, rulers, and locations Local 20
Identify natural hazard Nature 15 + hazard’s CR
Identify a common plant or animal Nature 10
Identify unnatural weather phenomenon Nature 15
Determine artificial nature of feature Nature 20
Know current rulers and their symbols Nobility 10
Know proper etiquette Nobility 15
Know line of succession Nobility 20
Know the names of the planes Planes 10
Recognize current plane Planes 15
Identify a creature’s planar origin Planes 20
Recognize a common deity’s symbol or clergy Religion 10
Know common mythology and tenets Religion 15
Recognize an obscure deity’s symbol or clergy Religion 20
Identify a monster’s abilities and weaknesses Varies 10 + monster’s CR

Monster Lore (Novice)

You can use this skill to identify monsters and their special powers or vulnerabilities.

Check: 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.

Table: Monster Lore

Creature Type Field of Study
Constructs, dragons, magical beasts Arcana
Aberrations, oozes Dungeoneering
Humanoids Local
Animals, fey, giants, monstrous humanoids, plants, vermin Nature
Outsiders Planes
Undead Religion


  • Skilled: When you successfully identify a creature, you gain one additional piece of information for every 5 ranks you possess in that Knowledge skill.
  • Expert: When you successfully identify a creature, you gain a +1 competence bonus on attack rolls, opposed ability checks, skill checks, and caster level checks against creatures of that kind (e.g., glabrezu demons, but not other demons or evil outsiders) for 1 minute. This bonus increases by 1 for every 5 ranks beyond 10 you possess in that Knowledge skill.

Recall Intrigues (Skilled)

You can identify feats and the class features of various classes with successful Knowledge checks when you observe the feats or class features being used.

Check: You can attempt a skill check to identify a feat or class feature when you observe it in use, similar to how Spellcraft can be used to identify a spell. The feat or class feature must have some observable effect in order for you to attempt the Knowledge check. For example, you can’t see the internal determination of Iron Will, so this ability can’t identify that feat. In general, if a feat or class feature creates a noticeable effect (such as the extra attack from using Cleave) or has a variable modifier a character must choose to use (such as Arcane Strike, Combat Expertise, or Enlarge Spell), it can be identified. If it creates a static bonus (such as Dodge or Lightning Reflexes), there’s no telltale sign to give it away.

Table: Identify Feats or Features

Task Knowledge Skill DC
Identify a class feature from a class that grants arcane or psychic spells Arcana 10+ class level when the feature is granted.*
Identify a class feature from a class with access to the druid or ranger spell list Nature 10+ class level when the feature is granted.
Identify a class feature from a class that grants divine spells Religion 10+ class level when the feature is granted.
Identify a class feature from any other class Local 10+ class level when the feature is granted. *
Identify a combat feat being used Local 10+ character’s level
Identify a metamagic feat being used Arcana 10+ character’s level
Identify teamwork feat being used Nobility 10+ character’s level
*Add 10 to the DC if the class is a prestige class.

The Knowledge skill required to identify a feat or class feature varies depending on the type of feat or class feature to be identified and is outlined in the Recall Intrigues (Knowledge) table above, along with the DCs of such skill checks.


  • Equipment (Library)—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.
  • Training—You cannot make an untrained Knowledge check with a DC higher than 10.

< House Rules: Skills

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