In the strictest sense, the demons are not a faction within Albion. They do not live or reside there in any real sense of the word. However, given the impact they have had on Albion’s history and the frequency with which they manage to claw their way into the world, it would be foolish to ignore them.
In Albion, you might meet a rogue demon that has managed to cross over but they are more commonly encountered in service to the Disciples of Morgana. Either way, you will have a tough fight on your hands!