Knowledge (Arcana)
Knowledge (Arcana) (Int; Trained Only)
You are educated in the field of study related to the arcane, which allows you to answer both simple and complex questions on that topic.
Specifically, Knowledge (Arcana) allows you to make checks to reveal information on ancient mysteries, magic traditions, arcane symbols, constructs, dragons and magical beast lore.
Check
Answering a question on an Arcane topic 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 magical beasts or dragons 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.
| Task | Skill DC |
|---|---|
| Identify auras while using detect magic | 15 + spell level |
| Identify a spell effect that is in place | 20 + spell level |
| Identify materials manufactured by magic | 20 + spell level |
| Identify a spell that just targeted you | 25 + spell level |
| Identify the spells cast using a specific material component | 20 |
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.
Special
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.