Oh How I could go into his for days. But I'll give you the short version!

In the Legion the game universe, There are three races. Each created for a specific purpose. The Malachitians, Oa'f'reet, Archalion, and Xinaran. Each had a task given to them to help the younger races. As the Oa'f'reet and Archalions started to try and take more responsibilities on their on, it created a rift. The Xinarans could no longer abide their actions and left from their homelands to go into hiding, letting the other three races do what they wanted.

As the Galaxy, and it's younger races spiral more and more towards violence, war, and damage to actually physical and hyperspace, they could no longer stand by.

They are coming back.