Halo 3 Mythic – Assembly Possibly A Campaign Expansion Too?

Addict Gaming Writes "If you look at the new achievements we posted, you’ll see that new skulls are going to be added into the game (remembering at this stage these achievements aren’t confirmed to be coming to Halo 3 Retail), these skulls being called "Heretic", "Assembly" & "Citadel". The Citadel & Heretic skulls can be placed in certain campaign levels quite easily, but the Assembly skull? I believe the Assembly skull to be a whole different story (Quite literally)."