Much of this stage has to do with the house itself, rather than Usher or his sister. The narrator notes the house's gloomy atmosphere and seemingly supernatural spook.
Usher’s illness is mysterious and potentially deadly. Suspense builds when he prophesizes his own death from sheer fear.
Madeline complicates matters in that she provides another possible source for Roderick’s madness. Her illness is equally mysterious, and her death and burial are additional spook factors. That Roderick thinks his mansion is sentient also adds to the growing list of supernatural superstitions dominating the plot.
All those eerie sounds and superstitious feelings have been leading up to this moment. Usher’s prophesies about his own death come true as he dies of fear.
We are as frightened as the narrator at this point. His flight from the house of Usher is full of heart-thumping suspense.
Man, we didn’t see that coming. This is FALLING ACTION taken quite literally. With the demise of the physical house and the demise of the bloodline, this story is pretty much done.
The House of Usher is totally gone; there’s not even any evidence that it once stood there.