Board Thread:General Discussion/@comment-11276487-20130724230617/@comment-10207438-20130725005949

Deadra can only be truly killed in Oblivion, and a Deadric Prince has total control within their plain of oblivion, and since the oblivion crisis it takes an outside force to move deadra from any plain of olivion. So they basically are trapped in a place where they are as indestructable as they so choose.

that means no.