The Tooin race was a branch of the Aan race of Aantooine.
The Aan and the Tooins both descended from a master species, unknown to experts, that split genetically into frilled and non-frilled varieties rather quickly in evolutionary time. As the species defined themselves, the Tooins were deemed inferior by their counterparts, due to the lack of a frill that the Aan possessed. This inferiority led to discrimination of the Tooins. To retain their being, the peaceful Tooin altered the Aanian names of the five moons of Aantooine to symbolize their god's love for them (i.e. Palanto, Manto).
The Aan were angered by this corruption of the original gods, which in their ideals did not view the Tooins with the same disdain. Aanian supporters, including some anarchists, began terror runs on Tooin monasteries and churches, killing any who followed the teachings of the new corrupted gods. Tooin leaders went over personal security agendas and took arms against the Aan.
Over time, the Tooins built up a world army that took control of the capital, Antoo, but by then, the power struggle had grown to include other star systems. The Tooins pushed outward towards what later became the Outer Rim Territories while the Aan took control of what later became the Core Worlds.
Now known as the Tooin Empire, the Tooins traveled to planets and gave them names based on theirs to claim ownership and to honor their original gods. Such planets included Tatooine, Dantooine, Ventooine, and Mantooine. A small band of discontent Tooins going by the name Ooin seceded, forming a mini Ooin Empire. They went on to found such planets as Velmooine.
As attention waned from Aantooine, a new species of beings began to populate their homeworld. Known as the Skeen, these demonic creatures could fly through the air, attacking towns and villages from the skies. Tooin troops were urgently requested to return to Aantooine to defend their cities. Simultaneously, Aanian forces wanting to reclaim their lands also returned to the planet and joined forces with the Tooins for the first time since before the events that led to their war with each other. However, even the combined forces of the Tooins and the Aan could not hold off the gargantuan amounts of Skeen that had collected on the planet, and all forces were wiped out. Those that remained on the colony worlds would later be subsumed by new waves of aliens, particularly Humans. Over time, Humans would also colonize Aantooine, yet were unaware of the impending threat of Skeen still inhabiting the planet.
The Tooins and their brethren, the Aan, would be forgotten until the arrival of the Spalgar on Aantooine.