Seven Seraphs is the faction I wanted to be in. But it was no where to be seen, nor was Osiris. (As far as I know) They took the time to include Dead Orbit (way to mainstream), New Monarchy (to hipster), and Future War Cult (eh). But no my 7 Seraphs. What the blam Bungie?
The Destiny database site has a few class items related to Osiris. Nothing on the Seraphs. I'm inclined to believe that Seven Seraphs is only accessed very late game, or was cut entirely.