Tought up a short, very sketchy, and conventional background story for GRIP but I wanted to weave in Rollcage somehow a bit too, and at least, "it's something ¯\_(ツ)_/¯ " .Sorry in advance for the grammatical errors, and logical fallacies, but feel free to check it out! If you have further ideas, or need of editing, just tell it. Names, factions, time intervals, everything is up to debate, and Rollcage, as it is, can be referred as an "oldtimer race show" or anything really.
At the Rollcage events, common interplanetary travels and planetary terraforming was a new technological achievement for humanity, but this brought trouble. A lot of big city on Terra, mostly the poverty stricken ones, rapidly became vacant or severely underpopulated due to heavy migration to worker colonies on other planets. Miner colonies later declared independence, resulting in armed conflicts. At the time, economic problems and crime rates skyrocketed around the vacant cities, so Rollcage events could be held. Terra's government, at first, overlooked the fact that armed, all-terrain flippable combat cars, going nearly at mach speed, ravaging their surroundings and each other at some places for the fun of it, since it had it's hands full with the ongoing conflicts with the colonists. Later on, it utilized these events as an entertainment source, to have the people avert their eyes from the globally rising problems, and ease their stress.
The human technological advancement eventually lured in alien visitors. Main diplomatic negotiations with the new species failed on either side, because the humans were greedy, and wanted the newly discovered race on their side in their trifles. Terra's government even going as far as to threaten them. Being fed up on this, the aliens turned on the human race in general, and all hell broke loose. An interplanetary all-out war began, which took ~100yrs and a heavy toll on their participants, but resulted in a temporary truce between the colonies, and Terra. The majority of human civilian population were pressed into enlistment and Rollcage events was a forgotten thing of the past. The combat cars' fate were either unknown, or being left on various places to rot. As time went on, the opposing forces turned out to be somewhat equal, causing the war to come at a standstill, eventually evolving into a very sensitive truce between the alien race and humanity. As the human population slowly began rising again, few of the long forgotten combat cars, along with the idea of combat racing were slowly rediscovered, and advanced further, resulting in the nowadays most famous GRIP races. But this time, pursued by the government/military, as the races existence was a severe threat to the hard-gained truce, since it's events could be considered as offensive behaviour by the aliens.
In addition to Liddo5: The lush, ever expanding jungle present on the planet is a result of an early, failed terraforming experiment, including mixing alien genes into terran vegetation. Liddo5 was intended to be a farm-world, but now, as the mutated vegetation is agressively taking over the planet, only a few operating research plant was left, having them as a site for further plantlife experiments, and a place for retreat.