Once you have access to a faery hill, you can enter Faery and start exploring. To our knowledge, no one has yet explored the Faery Sea to find out if the map wraps east to west or if there are additional regions yet to be discovered. Other than the Faery Sea, Faery consists solely of forest provinces, with an occasional city thrown in. They buy mithril, with an occasional city also buying gate crystals. Elfstones no longer protect against these encounters.
Nobles using conceal self are safe from harm.