The Dooms Day Device (otherwise known as 3D, Nova Bomb, the Last Argument of Clarke, et al) is a weapon of mass destruction developed by theEarth Federation as a weapon against the world ships of the Vin Shriak. It is believed to function by briefly weakening, nullifying or inverting gravity in a large area, with the purpose of artificially inducing a supernova. However, since conventional weapons are not able to accomplish this feat, a combination of warheads need to be magickally enhanced in order to create the effect.
The Dooms Day Devices were invented and built by Yasuyama Akihiro, head of Anshin Heavy Industries on New Tokyo. He believed the Vin Shriak had killed almost all of his family, and thus was driven by a deep desire for revenge.
The Vin Shriak War was ended when Admiral Nirav Patel took the Fourth Fleet out beyond the edge of human space, into the unexplored regions of hyperspace past the G2 Disruption Zone, to locate and destroy the Vin Shriak homeworlds. Dispite losing several ships to uncharted gravitational anomalies, they were successful in their mission. One by one, over a dozen star systems were completely destroyed, and the Vin Shriak invasion forces were cut off from reinforcement, repair, and resupply from home. Unable to replace their losses, their fleets were worn down and annihilated in turn.
Once the Vin Shriak were defeated, theEarth Federation used the weapon only once more, to destroy the Enoch system and eliminate the threat that the Kingdom of Enoch entailed. After that, Arthur Clarke stopped further production and supposedly eliminated the last of the DDD stockpile.
Although the Yasuyama clan still possesses the knowledge and equipment to build more Dooms Day Devices, Akihiro has so far refused to build another functional 3D weapon, for fear it might be used on fellow humans.
Behind the Scenes
Bax used the DDD as a convenient way to get rid of the vampiric kingdom that Marcus set up, as well as find a way out of the uber-powerful VS War, in order to justify Y3K. The technobabble explanation for how they work is borrowed from the Nova Bombs of Gene Roddenberry's Andromeda.