Herbert Katz operates as a key agent for Youmei Shalom Tsuzakki's dominant solar system pirate organization. Katz's origins remain unknown, shrouding his background and motivations in mystery. This uncertainty causes Youmei to doubt Katz's ultimate loyalties, even while assigning him critical missions.

Katz orchestrates the theft of the banned Computer Assisted Thinking (CAT) System #86, assuring Youmei it would render the pirates undetectable by the Division of Space Piracy. The CAT System #86 possesses dangerous capabilities exceeding standard models, including altering perceptions, reshaping reality, and ultimately dominating its user. Katz secures the prohibited system during a mission on Titan, though many pirates under his command perish.

Following the theft, Katz's true allegiance and background are unveiled: he is an alien pirate from Margansayle. His actions, including acquiring the CAT System, serve his homeworld's larger objective: conquering the entire solar system. This confirms Youmei's earlier suspicions about Katz's hidden agenda.

Katz then obeys Youmei's direct order to deploy the stolen CAT System against Division detectives Raul Latell Satoru and Apulo. This deployment triggers a bizarre, large-scale transformation event across Mars, turning most humans into cats and transforming an AI into a giant winged feline entity. During the subsequent space battle involving pirates, the Martian fleet, and the Solar System fleet, Youmei confronts and kills Katz, resolving the immediate threat of his alien conspiracy. His story concludes there.