How does the narrator of “the fall of the house of usher” react to his glimpse of usher’s sister?

The narrator seems to be shocked and frightened at his glimpse of Usher´s sister. As the narrator gets the first look at her face, he is stuck by the similarity between Roderick and the sister, there he learns that they are twins and that there was a very strange bond between them.

Ithink that story needs some revising. hmm some academic language perhaps? and sylvia is but i do think that rainbow is spectacular