This is none other than the home timeline of dimension-hopping bad-guys from the ‘Infinite Worlds’ background detailed in GURPS Time Travel. This turns out to have been an world-spanning Anglo-French empire which had collapsed in global war in the year 1902. Only Australia survived more or less intact; A cabal of scientists called ‘The Centrum’ seized control and rebuilt society along ‘rational’ lines. These same scientists discovered the secret of cross-parallel travel. In contrast to the other five worlds, we get very little description of the globe itself; instead the space is taken by their cross-parallel organisation, technology, and philosophy. We learn why they oppose Homeline (or Secundus, as they call them), and what they’re really trying to do.
Personally I’ve never found the default ‘Good Homeline vs. Evil Centrum’ totally satisfying; Centrum aren’t quite dark enough to be a really nasty villain, and to me a ‘shades of grey’ setting needs more than two sides to be interesting. A sidebar “Centrum Light” shows how you can make Centrum into the good guys; it suggests giving cross-parallel travel technology to Reich-5 from AE1 (in which the Nazi’s won WWII) to give them really nasty opponent.
Unlike Homeline, Centrum is ruled by a single world government, and has a unified technocratic English-speaking culture across the entire planet. Centrum is a totalitarian, homogenized world-state, and the only world other than Homeline to have a major parachronic program.Centrum is a socialist technocratic meritocracy; the government provides all employment and handles the economy, which is bolstered by the massive resources acquired from other worldlines. They believe other worlds should be aiming to follow their example and have a dedicated program of supporting political and economic groups that reflect their own values — stability, meritocracy and an unconscious prejudice toward speakers of English. They view the mix of competing government agencies and private companies from Homeline as dangerously anarchic. From a Homeline perspective Centrum seems authoritarian and repressive, whilst from a Centran perspective Homeline seams anarchic and unbalanced – with serious social problems from which Centrum does not suffer.
Its point of departure was in 1120, when the White Ship carrying William the Aetheling, the heir of Henry I of England, did not hit a rock in the English Channel. William’s survival precluded The Anarchy and the Hundred Years War, and ultimately the “Anglo-French Empire” became a world-spanning power, with technological progress centuries beyond that of Homeline.
However, in 1902 unknown rebels decapitated the ruling house by detonating a nuclear device in London. The resulting succession wars (which included nuclear and biological weapons) wiped out much of humanity and reduced most of the survivors to preindustrial barbarism. But Terraustarils (Homeline Australia) escaped much of the destruction, and the techno-military cabal known as “The Centrum” that took control there ultimately extended its authority across the globe.
Centrum is located three quantum levels away from Homeline, and as such the two worlds cannot directly send travelers to each other. As a result, both parties fight out their war in the Quantum 6 in-between (and to a lesser extent, in the Quantum 7, as Centrum is attempting to shift Homeline Quantum 6 echoes towards itself for the purpose of denying Homeline access to those worlds and “saving” their populations from Homeline anarchy.
Centrum is located on Quantum 8.
Local year is 2027.
Technology levels: TL8-9