User blog comment:ImperiexSeed/Supernatural Mysteries/@comment-3481504-20130307031256/@comment-5619706-20130307172257

Yes, I think they can. They are indestructible, after all. Unless the outer space is filled with numerous random Bones of a Righteous Mortal Washed with Three Bloods of the Fallen, then I don't think there is anything that would hamper their life.

But now that I think of it, I prefer them having to live in Purgatory to begin with (later sealed and replaced by a new earth), and that would clear up the creation timeline on whether the earth or the leviathans were made first.