Halo: The Master Chief Collection Season 5 - Anvil (2021)

Titled after both the Anvil Initiative and ANVIL Station, Season 5 added the AKIS and Mariner helmets into Halo: Reach, years after being teased in promotional material for the Defiant Map Pack in 2011, alongside nameplates and additional cosmetic customization options to Halo: Reach and Halo 3, including 12 armors from the cancelled Halo Online for the latter.