This story explores a family so isolated from the rest of the world that they’ve developed their own supernatural barriers to interacting with it. The House of Usher exists in its own reality, governed by its own rules and with no interest in others. Such extreme isolation forces the family members closer and closer to each other, again to a supernatural degree, and inexplicable to any outsider.
The narration is set up in such a way as to maintain distance between the readers and the Usher family. This highlights the impenetrable isolation of the story’s main characters.
Roderick and Madeline's extreme isolation from others created a situation in which their unhealthy relationship could continue unchallenged for years.