Arcana is a knowledge type skill linked to Intelligence. It can be used to gather knowledge on magical related topics.
Make an Arcana check to recall a useful bit of magic related knowledge or to recognize a magic-related clue. You require training in Arcana to remember knowledge about the Far Realm
You can make an Arcana check to identify creature from elemental, fey or shadow origin, or with the construct keyword.
Detect Magic (Trained Only)
You can use your knowledge of arcane to identify magical effects and sense the presence of magic.
- Identify Conjuration or Zone: Minor Action.
- DC: Moderate DC of the conjuration or zone's level.
- Success: The creature identifies the power used to create the conjuration or zone, and knows the effects and keywords of the conjuration or the zone.
- Failure: The creature can't try to identify the effect again until after a short rest.
- Identify Ritual: Standard action
- Identify Magical Phenomenon: Standard action. The creature must be able to perceive the phenomenon.
- DC: Hard DC of phenomenon's level. If it has no level, use the hard DC of the creature's level.
- Success: The creature identifies the phenomenon’s power source and other keywords, if any, as well as the phenomenon’s basic purpose if it’s not obvious. If a magical ritual created the phenomenon, the creature identifies the ritual and is familiar with its effects.
- Failure: The creature can’t try to identify the phenomenon again until after an extended rest.
- Sense the Presence of Magic: Standard action. The creature attempts to detect each source of magical energy within a number of squares equal to 5 + its level, ignoring all barriers.
- DC: Hard DC of the creature’s level. The creature automatically succeeds in detecting any source of magical energy within range that is five or more levels lower than its level.
- Area of Detection: You can detect magic within a number of squares equal to 5 + your level in every direction, and you can ignore any sources of magical energy you’re already aware of. Ignore all barriers; you can detect magic through walls, doors, and such.
- Success: You detect each source of magical energy whose DC you meet. You learn the magic’s power source, if any. If the source of magical energy is within line of sight, you pinpoint its location. If it’s not within line of sight, you know the direction from which the magical energy emanates, but you don’t know the distance to it.
- Failure: The creature detects nothing, or nothing is within range to detect. The creature can’t try again until after a short rest.
- The sage hireling gives a +2 power bonus, increasing to +3 at level 15 and +4 at level 25.
Arcana utility powers
Characters trained in Arcana may select a utility power in place of their class power (but not from a paragon path or epic destiny)
- Arcane Mutterings - Level 2[PH3:165]
- Arcane Senses - Level 2[PH3:165]
- Studied Casting - Level 2[Dr385:80]
- Cave Sight - Level 2[DSH:57]
- Experienced Arcana - Level 6[PH3:165]
- Insightful Warning - Level 6[PH3:165]
- Warp in the Weave - Level 6 [Dr385:79]
- Demonic Bargain - Level 2[DSH:69]
- Elemental Countermeasures - Level 16[PH3:165]
From PHB to essentials, the following changes exist but not published in the errata documents:[RC:133]
- The DC for the conjuration or zone was changed from 15 + one-half level to moderate DC of the target's level.
- Identify Magical Effect and Identify Ritual were merged into Identify Magical Phenomenon, and changed from DC 20 + half level to Hard DC.
- Sense the Presence of Magic was changed from 1 minute to standard action, and had DC changed from 20+half level to Hard DC. Additionally, it was changed from requiring an extended rest to try again to a short rest.