Darth Onasi, or whatever you want to call him, was a Republic Captain and the first permanent member of Rarth Devan's travelling circus, after original first member Trask Ulgo left to pursue other ambitions, supposedly...
Darth Onasi has serious problems with trust. He doesn't trust you. He doesn't trust Devan, he doesn't trust Trask, he doesn't trust The League even though he's a member, and he doesn't trust himself either.
This distrust is thought to be a trait imprinted onto him by Darth Cryer, who believes distrust is an effective shield, for the sole purpose of annoying her competitor in the Circus industry, Rarth Devan. At the time, Cryer was attempting to assemble her own Circus of Wonders and so desired to eliminate the competition from the inside.
The plan failed however, and after having a good old moan at her partners-in-crime, Cryer decided to scrap the plan and simply try to beat them fairly. Onasi travelled around the Galaxy with the Circus of Devan and eventually, along with his Circus buddies, managed to accidently save the Galaxy by destroying their latest venue, The Star Forge.
Darth Onasi then settled down and was recruited into The League's Espionage division by his Circus predecessor, Trask. He is currently working as a double-agent, infiltrating potential enemies of The League and learning their motivations.