The Terran Combine is the largest polity on Terra Secundus by size. Among the polities of Terra Secundus, the Combine is not just the largest, but also the most unique. It has a semi-confederal government structure.
The earliest part of the Terran Combine was originally established in 1890 CETT by merging several polities of the natives of Terra Secundus. Originally called the Comradeship, it was founded from the beginning as a semi-confederal state, with individual polities remaining existent.
The Great Evacuation
Delegates from the Whirosian Central Empire arrived on Earth, secretly, in the beginnings of World War II. with the rulers of National Socialist Germany. They offered a secret evacuation program in which the most fit of the Germans would be sent to a new extraterrestrial colony already being set up by the Empire. (Near the end of the war, National Socialist Germany would create a new colony in Antarctica.) This resulted in the establishment of the New Terra Colony near the borders of the Comradeship, which began operations in 1949.
For a long time, the whiros imposed a no intervention policy between the colonists and the natives. This was intended to reduce conflict between the races. The whiros also has such policy intact between the whiros and the colonists once basic requirements were set up (around 1950). While the whiros didn't intervene with the colonists, they did watch its development through a Watcher satellite set up in Terra Secundus' orbit.
Unification of the Races
Twenty-five years after the New Terra Colony began operation, the whiros lifted the restriction to intervene with the natives, although several restrictions still apply. With this in mind, the colonists met the natives' Comradeship. After language and cultural barriers between the two different, similar-looking but mutually-alien, species (colonists and natives) were broken (colonists studied the language of the natives, which is similar to Japanese, and vice versa), the colonists proposed a new federation to reconcile relationship between the two races. This was accepted by many natives, and shortly after, the Terran Combine was established in 1974 by expanding the Comradeship's borders into the New Terra Colony.