The initial vidoc states something tried to stamp us out, I take the vagueness to mean that "something" hasn't been revealed. Some sites falsely reported on the Cabal, but I cannot verify Bungie ever said it was the Cabal that tried to stamp us out, or the Fallen for that matter. What brought about our near extinction? I would love to get a dialogue going, as I'll be preparing a topic about this very subject on our website.