Can't find thing for Lord Rhydder's estate (Spoilers in descutions)

[Rohomild]

I've climed almost all the way to the top of Lord Rhydder's castle, but I've come to an elevator I can't access because I need a key. How do I continue?
Looked arround the previous floors and in the basement. Found a morror portal to a little church outside, but not key to be found.

Edit: Nevermind. I was in Cadaver Keep and not his estate.

[Forgotten Lands]

The key to the lift at the top is gotten from one of his mercenaries at the Inn in Sepulcher. There is unfortunately no other way to gain access.