A neutral character would not be able to enter Dyster without a key. This means they can either borrow a key from a follower, or have the follower let them in directly. They would also need to leave using the key. (The exception would be summoning sigil/faerie rings/other long distance teleportation methods, although characters who arrive without an invitation will be immediately cast out.)

A Fog follower's home is only present in spooky Dyster! The old, abandoned Dyster will always remain old and abandoned, with no new buildings or residents.