The Colonials are the Human population of the Twelve Colonies of the Cyrannus System and the various colonies and settlements associated with them.
Colonial History is undoubtedly well known to any who are reading this, but a short recap is in order.
The History tells that Humanity originated on the planet of Kobold and grew and flourished into a great and mighty civilization. But it was a civilization that existed on and exploited its home planet to the point where it became virtually uninhabitable. In order for Humanity to survive the Ancestors built a Fleet and the Thirteen Tribes of Humankind, plunged into the unknown of Space where, after much time and trouble, they found a home in the a star system of three suns and twelve shining jewels of planets.
Twelve of the Tribes were delivered to this new home, the Thirteenth was lost and, according to legend, found a new home on a planet known as Earth.
The technology of space flight was deliberately abandoned, as was much advanced technology, by those that reached this new home, as the race sought to renew itself with a simpler life. Soon the knowledge of the other Tribes and their fates faded from living memory, becoming only a myth.
Eventually though, Humanity began rediscovering the lost sciences and once again ventured forth into Space. Only then did the different Tribes rediscover each other.
Things were not easy at first. There were tensions, differences and suspicions. There was some strife and even war, but eventually the Twelve forged anew their ancient friendships and set forth a new government, a new Council of Twelve that established peace and prosperity for all the Twelve Colonies.
Over time the Colonials spread out through Space, discovering new worlds, new races and new civilizations. Even, in several cases, lost human populations from the time of the First Exodus.
Eventually one of the new races, the Hasaris, a peace loving species that had extended friendship to the Colonials, called out for help in a war that had descended on them from virtually nowhere. A strange new race, a race of sentient machines, called Cylons, attacked the Hasaris, seeking to destroy or enslave. The Colonials went to their friends aid and thus began the Thousand Yahren War with the Cylon Empire.