Reverse Babel is a large facility that was developed in secret by means of Elysium's vast computational power and ability to synthesize technology far in advance of current technological standards. It served as an incredibly powerful weapons platform, with strong shielding and cloaking abilities, point-defense laser batteries and vast reserves of automated Zauber Soldats, Archaisms, Magic Knight and spirits.
Reverse Babel also served as a factory where this advanced technology could be reproduced in high numbers. Technology reverse-engineered from artifacts such as the Sonorous Seashell and Monarch's Regalia was integrated into its design as well as numerous traps. Notably, it housed a great optical weapon, Keraunos (天の電), referred to as the ultimate weapon,[JP 1] which made use power drawn from the Septium veins to launch a destructive blast through use of a sub-orbital Combat Shell, which further amplified its power. This weapon could be automated to fire based on humanity's emotions. Erika Russell comments that no technology should be able to fire at such lengths with such accuracy, however, this proved not to be a problem for Elysium.
Reverse Babel is a conical structure with many layers leading into a central area where the Keraunos weapon is located. It is filled with spiritual energy and a spiritual barrier surrounds it, said to be impenetrable for even a Railway Cannon. Aside from its powerful spiritual barrier, Babel uses advanced cloaking technology which hid it from being detected as it was constructed. It used the the Orbal Net and Sonorous Seashell to manipulate the schedules of the ferries so they would not discover its presence. many parts were constructed at the Reinford Arsenal, including the Keraunos.
After Supreme Leader Rufus Albarea is destroyed, a recording of him plays and the installation is revealed as it decloaks and emerges from the middle of Lake Elm. Its primary move is to use Keraunos to destroy the Juno Naval Fortress, leaving a massive crater. There were no casualties due to the fortress having been emptied for maintenance. With the ultimatum set that it would fire again upon Baratier Airbase in Calvard, efforts from numerous parties quickly scrambled to counter the weapon.
The heroes gather on the roof of the Orchis Tower and watch as the battle ensues. The Crossbell Police Department and Crossbell Guardian Force use multiple watercraft to start the battle, engaging with automated Zauber Soldats. Capua Family and Neinvalli Bobcats arrive with bracers to reinforce them, along with allies such as students from both Thors Military Academy and Thors Branch Campus. Vita Clotilde summons several Ouroboros airships to help, accompanied by forces from Zephyr, the Red Constellation and the Stahlritter. Reverse Babel counters with larger numbers of Helmodes, Asmodine units and point defence lasers. The Gralsritter send five Dominions under the command of Thomas Lysander to help protect the forces, with numbers 2, 3, 5, 9, 11 sighted. Merkabah 8 had been previously damaged by Zoa Gilstein and 9 was commanded by Scarlet and Wald Wales, with support from Wazy Hemisphere on the ground.
The party make their move when the Arseille II, disguised as the Courageous II arrives. They are teleported onboard just as a barrage of fire disable the cloaking and reveals the true appearance. As the Arseille was developed in secret, Elysium had no data on it and the Zauber Soldats were unable to respond to the new threat. facing an error in its ability to accurately defend itself, the Keraunos weapon is fired at the Arseille II, however the blast is deflected by five of Erebonia's strongest warriors: Aurelia Le Guin, Victor S. Arseid, Matteus Vander, Wallace Bardias and Vandyck, all of whom have their weapons enchanted by the Hexen Clan. This blast de-powers the forcefield enough that the main cannon can punch a hole through it, and the party are teleported in. En-route, Zoa Gilstein teleports in and attempts to attack them spiritually, missing them but succeeds in separating the party into two.
Inside, the parties independently move around the structure in an attempt to reach the middle. they beach fall prey to various traps and defences based on reverse-engineered artifacts, and come to each others' aid, but they are unable to reunite until just before the end. They face off with Ishmelga-Rean and Zoa Gilstein, but are no match against his limitless strength until they can delete Elysium. In his dying throes, Ishmelga transfers control to the 'anger of humanity' which will cause Keraunos to fire repeatedly at wherever humanity's rage is directed. The facility begins to overheat to dangerous levels and the party withdraw, with Rufus staying behind.
Rufus uses the communications systems to send a message out to the world, directing all hatred unto him as he claims responsibility for the part he played in the Great War and all the conflict and events that have transpired since. This is enough for the greatest target of anger to be Rufus himself and Keraunos targets Reverse Babel, Rufus's current location. At the last moment, a party consisting of Lloyd Bannings, Jusis Albarea, Nadia Rayne, Swin Abel, Lapis Rosenberg and Zeit rescue him before it destroys itself.
- Babel is the name of a mythical tower constructed by ancient humanity in the Bible in their attempts to reach Heaven. God cast down the tower and changed all of the languages of humanity so that they could not communicate effectively to attempt to build the tower again, acting as an explanation for all the different languages.