Complete any co-op level on Legendary difficulty.
Halo 4: Survive Spartan Miller (Ep.5 Ch.1) of Spartan Ops on Heroic or Legendary.
Halo: Reach: Complete every level of the game on Normal difficulty.
Halo CE: Complete The Library on Heroic or Legendary difficulty without dying.
Halo CE: Find and claim the Malfunction skull in remastered mode.