I was wondering who exactly lives in the various Oblivion realms. For example, in the Shivering Isles, we see lots of humanoids/people of the various races of Tamriel. How did they get there? Are they Daedra? Are they dead and it's the representation of their souls that were claimed by Sheogorath? What about the other realms, like Hircine's realm or Azura's realm or Mehrunes Dagon's realm - do "people" live there too or are there only the Daedra? In TES IV, there didn't seem to be many Tamrielic people living in Dagon's Deadlands. Is there an explanation as to why some realms have "people" and other don't?

Sorry for the long post but I appreciate all the answers!