Armored Response Coalition

The Armored Response Coalition (ARC) is a global military crisis-relief initiative formed by the combined efforts of the Allied Nations and Dr. Samuel Hayden to oppose the Hell invasion of Earth. The ARC appears in Doom Eternal.

History
The ARC was established by the Allied Nations in 2151 to succeed where modern militaries proved ineffective against the Hell invasion. Dr. Samuel Hayden, who served as the ARC's Lead Director and oversaw all aspects of ARC weapon and tech development, provided the ARC with cutting-edge Argent-powered technology as he re-purposed Earth-based UAC facilities, which were unaffected by the invasion due to their remote locations and high levels of automated security, to mass produce weapons to the initiative.

Since its inception, the ARC began running operations from the Mobile Command Carrier, a seaborne command center designed for long-range strike operations, and was tasked in locating the source of the Hellgrowth infestation and shutting down the emergence of Hell portals and closing the gate between dimensions. Under Hayden's guidance, the ARC was committed in an aggressive research and development program in pursuit of new technologies to face the Hell threat head-on. But in spite of the advanced technologies, the ARC and humanity was fighting a losing battle.

The ARC launched a failed attempt to eliminate the Super Gore Nest in central Europe, the original source of the Hell invasion, which saw the complete annihilation of 3 NATO Shock Troop battalions and 18 thousand coalition Special Forces units along with the loss of 32 vessels. The ARC suffered the loss of Hayden after committing in a failed counterattack coordinated by Hayden in Operation Hellbreaker. Though ARC soldiers managed to retrieve Hayden's robotic torso and had him closely guarded and tended by a crew of scientists.

The ARC's future soon changed for the better when the Doom Slayer came to Earth. Initially, the ARC were wary of the Slayer's intentions despite of his clear hostility to the demons until his actions of killing the Hell Priests and the destruction of the Super Gore Nest gave human forces the advantage to overcome weakening demonic forces on all fronts. The war against Hell ended with the Slayer destroying the Icon of Sin, and with it causing the majority of the demonic force to disperse from Earth.

Trivia

 * Known members of the Armored Response Coalition, apart from the non-cultist UAC remnants, include the United States, NATO, and most of Continental Europe.