Onegas' Demiplanar Prison

"There is no free will, only MY will"-Onegas the HeartlessOnegas, a bizarre fusion of undead and machine, was imprisoned long ago in this continent-sized demiplanar fortress with his many creations both magical and technological, plotting the conquest of all things. His fortress is of the high-technological sort, far more advanced than almost anything on the Planes. Onegas, it is said, was once a normal Lich, like Vecna and Azalin were before "ascending". One day, the Prime world Onegas lived on was invaded by beings of extremely high technological development whose goal, it seemed, was to purge the universe of magic and magical creatures. They didn't even acknowledge that the Outer Planes existed. During the wars on the planet between the forces of Magic and the invaders, Onegas captured some technology for study, and eventually (over the course of many years) "upgraded" himself with findings based on his research. He also quietly salvaged dead humans and elves, and began experimenting on lesser "Necroborg" varieties. After around one thousand years of fighting with the invaders, the natives finally, using a powerful series of Quest spells, managed to drive the invaders permanently from their world. The spells were so powerful that most of the world's gods gave their lives in order to cast it.During the dark years of rebuilding that followed the end of the war, Onegas finally made his move, and proceeded to conquer the entire planet with his hybrid armies, forcing all of the world under the yoke of slavery. Onegas then turned the entire world into a gigantic factory, in order to mass-produce his soldiers in preparation for the conquest of other worlds.And Onegas managed to do just that.With his magical and technological knowledge growing with each passing year, Onegas managed to improve his armies (and himself), conquering every world in his path.Then Onegas made his first mistake: He turned his attention towards the Planes.Deciding that Sigil would be the ideal fortress to launch his campaigns, Onegas sent a scout into the Cage to find out everything about the city (possible defenses, good launching points within the city, etc). When the scout never returned, Onegas was intrigued. Finally, after all the countless years since Onegas started his campaign, a challenge had arisen...none other than the Lady of Pain, that is.After gathering as much information on Her Serenity as possible, Onegas began creating Super Soldiers armed with every defense imaginable, and sending them into the city to assassinate the Lady. When each failed, Onegas improved upon the modules. This pattern continued for hundreds of years, with Onegas' attention divided between taking Sigil, and conquering the Prime, until one day, the Lady simply closed the city off from the worlds Onegas had conquered, effectively dooming Onegas' invasion attempt.Now, Onegas had made other enemies on the Planes as well, and these proved to be the eventually downfall of Onegas' ambitions.On each world Onegas' conquered, all sentient beings were carefully catalogued, and reprogrammed to serve and worship only Onegas. Therefore, as Onegas spread this taint throughout the Prime, a few scattered pantheons grew upset, and at first, tried to deal with Onegas themselves. But their concerns died out as their worlds were destroyed or conquered, with all of their worshippers brainwashed or killed, leaving the gods they worshiped as powerless husks or mere, however powerful, mortals. Finally, the more prominent powers of the Multiverse began to notice Onegas and his ever-expanding godless empire. The Good Gods, like Bahamut, viewed Onegas as an abomination, and his Empire as an expanding cancer on the Prime. They decided to send powerful celestial armies into Onegas' territory, in hopes of ending Onegas' reign of terror once and for all. But to their horror, not only did Onegas and his souless armies manage to hold off the Celestials, but Onegas now turned his sights towards the Outer Planes.All attempts by the Good powers to eliminate Onegas himself failed, as no matter how many powers joined in the fight against Onegas, he himself for some reason was untouchable by even their most powerful divine members.By this point, the Good powers realized that Onegas was far more sinister and insidious than anything they had encountered so far, and they decided to petition the Neutral Powers for help.The Neutral Powers, realizing that Onegas not only represented a threat to the balance, but a force that could eventually totally destroy the Outer Planes, decided to join with the Good powers in combating Onegas in all his advanced technological might.But they too failed, and this time, many of their followers, such as Aasimon and Rilmani, returned to the Outer Planes as Cybernetic servants of Onegas, who proceded to wreak havok on Mechanus, the Outlands, and the Upper Planes.But meanwhile, back on the prime, Onegas had made some stunning breakthroughs of his own regarding the nature of the Outer Planes and the Gods, and their dependence on Belief for their very existence.Using this knowledge, Onegas managed to create the ultimate weapon: the Belief Nullifier, a gigantic, rectangular, planet-sized weapon of immense power, which was capable of destroying entire planes with a blast composed of something Onegas called "Anti-Belief". After the Gods discovered this sinister device, they redoubled their efforts in a last-ditch attempt at destroying Onegas, but once again met with failure.Finally realizing that they couldn't touch Onegas or his empire, they decided to throw everything Onegas owned into the Ethereal Plane as a huge, inescapable demi-plane, using ever power in their arsenal to do so.The Multiverse had just survived yet another crisis, and in order to prevent such a powerful being like Onegas from appearing elsewhere, the Powers decreed that no world possessing technology more advanced than "medieval" or "Renaissance" would ever be allowed to possess magic as well.The question remained about what to do with the research and advances Onegas had made.Since no god could agree to let any other guard such a powerful portfolio as cybermancy, all the powers combined their might to created a god-beast forged of a shred of every power's essence. This guardian functioned as a mindless sentinel, entrusted with the portfolio of technomancy and the purpose of keeping anyone from utilizing it. The beast had might greater than any single power, but has no will other than serving its one purpose of destroying those who seek to combine magic and technology beyond the limits set by the combined will of all the powers.This rule has held sway over the Prime for aeons, but leaks are beginning to occur on some worlds........(The Gates of Firestorm Peak, The Tale of the Comet, and the Sheen Invasions on numerous Prime Worlds) As for the Belief Nullifier, that horrific weapon disappeared shortly after Onegas and his empire were banished to the Ethereal Plane. Some say it lurks between the spheres of Carceri, others say it was transformed into a new Cube on Acheron, and still others believe it was placed by the powers somewhere in Pandemonium's fourth layer. Perhaps it is a dark better left unanswered.