Operation Overlord Revenge

Operation Overlord Revenge (オペレーション・オーバーロードリベンジ) was a largescale joint operation by Academy City and the Anglican Church against R&C Occultics in Los Angeles, United States of America.

Principles
The operation was planned to be a rapid strike, landing on the West Coast and attacking R&C Occultics HQ in downtown Los Angeles, aiming to destroy the control server before they could break it down and transport it out. However, as the area had been changed into a Rosicrucian hideout without the government noticing, the joint force was heading into unfamiliar territory. As such, some field bases would be constructed on the way to claim territory for themselves, mitigating the possibility of becoming trapped between the building's defenders and another group attacking from behind.

The Academy City field base visited by Touma's group was described as a moss green tent, in the shape of a garage-like tunnel and set up on a basketball court between two skyscrapers. The inside was described as looking like a high-tech car factory, with a large work table moving up and down, surrounded by jacks and robotic arms, and metal rails and cranes overhead, carrying machinery around and stacking metal containers (some holding Five Overs), disorganized at the time Touma's group came.

Weaponry, equipment and vehicles used by the Academy City forces included attack helicopters, tanks, armored trucks (including at least one 8-wheeled truck),  a black boomerang-shaped bomber, and Five Overs, including mainline Railgun and Meltdowner models, and the Outsider Accelerator model.

However, the joint forces failed to properly account for R&C Occultics's capabilities as a company combining both magic and science. The firewalls and standard electronic defenses of the automated weapons could be bypassed through the use of magic, which would allow the enemy to hijack them. Additionally, the capacity of the Logistic Hornets as a meteorological weapon greatly bolstered the effectiveness of Citrinitas's sand.

Background
In late December, R&C Occultics was formed by Anna Sprengel using hidden Rosicrucian treasure reserves and multiple pawns worldwide, a giant IT company specializing in magic. Rapidly expanding, it acquired numerous slave companies, one of which was Melzabeth Grocery's Space Engage, with R&C Occultics taking the Logistic Hornets for its global drone delivery system rather than spaceflight. Melzabeth stayed to try and prevent her work from being misused but was unsuccessful.

Due to recent events and the company's circumstances, neither the Magic Side or Science Side knew how to properly respond to it, and it rapidly grew in-between them. The magical knowledge that the company distributed to the masses caused numerous incidents which overloaded the responsive capacity of organizations such as Necessarius, with extensive injuries among Academy City's esper population, as well as Operation Handcuffs spiralling into a slaughter due to the company's distribution of the Coins of Nicholas.

Following the extensive chaos and casualties on December 25th, the Anglican Church and Academy City joined forces for a counterattack. Through a lead in the records of a Cayman Islands bank and tracing data trails, they were able to locate R&C Occultics HQ in downtown Los Angeles.

Chronology
The operation was devised and initiated late on December 25th and December 26th, after the discovery of R&C Occultics HQ in downtown LA and with authorization from President Roberto Katze. The joint forces managed to enter the city from the coast and had begun setting up temporary bases, however they were swallowed up by the giant sandstorm created by Citrinitas and the Logistic Hornets, trapped in the sand along with the rest of the city's 30 million people, at some point prior to 2AM LA time.

Following the mass disappearance, a small infiltration team consisting of Stiyl Magnus, Kanzaki Kaori, Index and Kamijou Touma were landed in LA, and found survivor Helcalia Grocery following a clue left by Melzabeth Grocery, but split after Kanzaki fell victim to Citrinitas and disagreements over Melzabeth's apparent role in events. Due to the circumstances, the US government could not authorize military action, though the NSA and CIA were waiting outside the city. Accelerator's trial was ongoing at the time so standard communication lines with the new Board Chairman were unavailable, though Archbishop Dion Fortune was able to communicate by remotely hijacking Qliphah Puzzle 545.

Following Fortune's conversation with Accelerator, the Sisters deployed themselves to aid Kamijou Touma in his struggle to prove Melzabeth's innocence and defeat the perpetrators attempting to frame her. During the following battle, the Sisters fought Five Overs brought for the operation, which had been hijacked by Citrinitas, who would once again deploy the sandstorm that had engulfed the city's population and the Overlord Revenge operatives. At the same time, during a charity debate in the White House, in which he had been criticized over the circumstances surrounding the events in LA, Roberto managed to identify Vice President Darris Hewlane (who had also been the US contact for Overlord Revenge and was secretly Citrinitas) as a traitor, resulting in a gunfight.

After Citrinitas's defeat, the personnel involved in the operation were freed from the sand along with the population of Los Angeles. However, when Stiyl and the Anglicans arrived at R&C Occultics HQ, they found the executives there already dead, having been killed not long beforehand by Aleister Crowley.

Trivia

 * The operation's name is likely derived from, the codename for the Battle of Normandy and the launch of the Allied invasion of German-occupied Western Europe during World War II.
 * It should be noted that overlord and overload have the same kana (オーバーロード, Ōbārōdo). Given the overall circumstances, Overlord is much more likely, though it should be noted that Overload could also fit slightly, given how the incidents caused by R&C Occultics distributing magical knowledge and tools had been overwhelming the responders (and others) of both Academy City and the Anglican Church over the past couple of days beforehand.