Opening the door just to the right of the spike pit

[Adamski]

I cannot find a key that it tells me I need.

It's the door to the right of the spike pit, and below Edril the spirit

>_<

 

[Adamski]

Bump

 

[Senneria]

North of where you fight the boss you can see the key down below, you just need to find a magnet. One of the bookshelves in the area should tell you where to find it.