The Outsiders are a kind of very powerful beings.
Outsiders are immune to most forms of magic.(ref)
The Walkers are Outsiders and include He Who Walks Behind and He Who Walks Before. (ref)
Known Outsiders Edit
- He Who Walks Behind
- He Who Walks Before
In the series Edit
In Cold Days, when discussing He Who Walks Before, Mac tells Harry there are three of them, Who Walk Before and two others. This may mean there are three Walkers in total, He Who Walks Before, He Who Walks Behind and one other.