There was a constant war among races. At one point biomachines called Weapons were created or just appeared and because this were a much bigger threat the races decided to join forces and fought in the big war what ended when they managed to destroy one of the weapons in Caelifer, which had been the battlefield and the rest disappeared to never be seen again (they went to hibernate in Acretifer). They all celebrated peace and decided to make the CEBSB or "Cultural Exchange Between Species Bill" 

I think it's allright