From Halopedia, the Halo wiki
The Anvil Initiative is a cross-training and evaluation program of the UNSC Armed Forces' Spartan Operations, operated in collaboration with the Swords of Sanghelios. The Anvil Initiative provides Spartan-IVs an opportunity to directly interact and train with Sangheili warriors in both shared War Games and live exercises aboard ANVIL Station. Anvil also tests hybrid technologies developed by the Office of Naval Intelligence, corporate partners, Sangheili artisan-armorers, and special research collaborations. The program was established alongside Project CRUCIBLE, which aimed to create a joint Spartan-Sangheili task force to begin building a robust relationship between the two species'.
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