I was really hoping that the Legion of the Damned would be worth a full supplement, and even this does not preclude it. I think this new Space Marine book is going to be huge, and I am starting to see why the book has more pages in it than other 6th edition codices.
via an anonymous source on Faeit 212
Legion of the Damned are listed under the elite section of the codex, as revealed in the new White Dwarf. Even though I have seen this entry, its very hard to make out, so no other information, sorry. They are revealed in shown pictures of codex entries, which includes Dreadnoughts and more.