The Katurians are a race of advanced humanoids. Though humanoid, Katurians do not look especially like Humans and require surgery in order to pass themselves off as Humans.
The Katurians are grouped into the Katurian Empire, an empire led by Shade Vassily. Shade Vassily was a cruel dictator, frequently massacring planets if they questioned his rule. Eventually, the rebellion succeeded and Shade Vassily was overthrown. In their last act before they were overthrown, the Imperial Council exiled Shade Vassily to a primitive planet, Earth, for punishment. They also sent a decoy and guard to confuse any members of the rebellion.
In 1924, the rebellion eventually did track down Shade Vassily in order to deal out more severe punishment. They sent down an agent with several Clockwork Mechanicals, though their research wasn’t perfect and the agent wasn’t properly disguised. They were able to detect any advanced technology, though Shade Vassily was also using clockwork technology. After some mistakes, Shade Vassily was eventually killed before his escaped from Earth. (NSA: The Clockwise Man)