(Disclaimer: This is a fanwork, not part of the GURPS canon.)
Paradox is a Quantum 5 that host of headaches all rolled up into one nice little package - the Secret is shot to blazes, the world is high mana, its people have been stumbling around who knows how many echoes for decades, the method of travel the reality uses doesn't seem to fit the rules of cross timetravel, there is a war going on between a Reich reality and this world, and it was created by another crosstime world some 60 years ago in that world's 2013.
Paradox is an extension of what appears to be an even older Time Travel organization called Topaz who it was originally thought had created a divergence in 1899 when a Jewish girl of about 20 became involved in the young Adolf Hitler's life. But closer study has shown very subtle historical differences as early as the 1880s. In any case, in 1900 the young Jewish girl saved his brother Edward and, from there on, his life took a dramatic turn. In 1906 instead of going to Vienna, Hitler went into the military as an officer and became noted for his use of the teachings of a Chinese general named Sun Tzu. When the Great War broke out, the men in Hitler's command suddenly got equipment that made resulted in victory after victory.
By the end of 1915, Austria-Hungry had won the Great War and, when the Kaiser tried to impose harsh treaty agreements, the very forces that had won the war quickly overthrew him. In the Kaiser's place the Phoenix Republic was set up along with League of Other Worlds which was to study mystical powers and contact other realms which they did in 1922 finding what appeared to be the Aryan tribe responsible for the Hindu religion there followed a mad crosstime/dimensional seek and find quest by the Phoenix Republic that continues to this day.
Even though the mysterious benefactor simply known at Topaz seemed to cut back on its supply of miracle machines in the 1920s it still supplied enough that the Phoenix Republic pounded the Italian fascists out of existence within a year of them coming to power. In 1923 Hitler wrote Erbe des Phoenix (Legacy of the Phoenix) that stated that the many religions of the world were in fact the memories of the last surviving tribes of the Aryan race. He then went on to say that knowing it was dying these last tribes of this Aryan race had seeded the varied races of man with certain aspects of themselves. The time had come to reunite these traits so the Aryan race, the godlike superpeople of the past, could again walk the earth. Ten years later as the PR was conquering the USSR, Hitler wrote Unser Kampf, which detailed a horrific alternative history that he stated, had been their destiny before Topaz.
Unser Kampf is in fact a study on the rise and fall of the Third Reich in great detail even to including the names of the people involved. This gives Homeline at least some idea as to the history of the Topaz timeline up to that point in its history.
In 1931 prodded on by invading Nazi forces from another history various Chinese warlords tried enlist aid from mystic forces they barely understood and had even less control over. The result turned China into total war zone with warlords fighting each other along with the otherworldly forces they had hoped to control. By 1945 China as secured and an attempt to strike back at the Nazis was made. That was when things got complicated.
Infinity's main headache is Paradox-1 uses something it calls Trinity Chronal Theory to travel quanta which doesn't seem to follow Parachronic Theory in any way Homeline understands. By 1950 the Nazi invaders were defeated but they had blown up their crosstravel equipment, so thinking it was simply creating alternate timelines Paradox tried to change the out come of the battle so a timeline where they captured the equipment intact was created. On the 25th try they succeeded and incorporated what they found into their own technology. Thirty years later Infinity quickly recognized what the Nazis had left behind: a two quantum Parachronic conveyor.
So the average Infinity agent dealing with Paradox has the prospect of dealing with 25 "alternate timelines" (Paradox echoes) ranging from Quanta 2 to 22 according to Infinity's all happily communicating with each other and a Nazi world (dubbed Reich-6) that had Parachronic travel some fifty years ago that was able to reach Quantum 5. Then there is Topaz which assuming the same rate of time as on most worlds would be around 2073 putting it in Homeline's future.
This is all ignoring the various military and humanitarian misadventures the various nations of Paradox-1 and its echoes have engaged in. Infinity estimates run as high as over thousand different parallel worlds have been involved. Of particular concern is that several of the realties Paradox-1 regularity communicates and travels to are in Quantum 3 and 8 and they can easily travel to other Quantum far outside either Infinity's or Centrum's ranges.
Paradox's formal method of "time travel" is called an Einstein-Rosen Bridge or ERB for short and they think that the act of traveling through time either creates or takes them to a parallel world identical to their past to the point of arrival. The range of their equipment was 100 years into the past before the recovery of the Reich-6 Parachronic conveyor. After that the range appeared limitless.
League of Other WorldsEdit
The League of Other Worlds monitors various time travel operations of its member nations in an effort to keep any conflicts from spilling over into the main timeline. It also allows membership to nations of other timelines that diverged before 1899 in an effort to prevent some of the wars that happened in its past.
Infinity and Centrum are both frighted by Paradox-1 and it has learned of their existence. However, it has not figured out "the proper changes in history" to directly access either of their realities. The League of Other Worlds sees merits and problems with both Infinity and Centrum but it don't consider them anywhere as dangerous as Reich-6 or some of its member nations who on occasion still go on a change the past to make our present better misadventure.
As a result it has made an offer for representatives from each reality to be members of the League of Other Worlds which was accepted but five times the number of representatives showed up then were supposed to. It was quickly discovered four groups of these were "alterantes" to the main Infinity and Centrum timelines.