Knowledge (planes) covers the Inner Planes, the Outer Planes, the Astral Plane, the Ethereal Plane, outsider creatures, and planar magic.
| Knowledge (planes) task | DC |
|---|---|
| Know the names of the planes | 10 |
| Recognize current plane | 15 |
| Identify a creature's planar origin | 20 |
| Identify an outsider creature's abilities and weaknesses | 10 + monster's CR |