Membros is chief interrogator for the Ministry of Science. With his body a testament to the dangers of careless Enerchanging, Membros takes great pleasure in his work and wishes to "perfect" the bodies and minds of his victims as his have been. He also has a habit of ending statements as questions, yes?
Membros was ordered to oversee the interrogation of the Pharoid Oziron Rael by Baron Daegon. Deciding to take a more hands on role after his officers' methods yielded no results, Membros joined Oz and the other Micronauts just as he admitted that he'd just been playing along and exaggerating his pain levels to his prior interrogators. Having not gotten to put his skills to work in quite some time, Membros made promises of the agony that would soon befall Oz before the Ministry of Science's flagship suddenly came under attack by a team of New Acroyears who were after Oz. Refusing to let them take him, Membros attacked the Acroyears who had grabbed Oz, inadvertently sending him flying towards the hull breach their entrance had created. After the emergency shields activated just in time to save Oz, Membros accused him of feigning ignorance as to why the shields came up with such perfect timing but was punched out by the Pharoid before he could finish.
After the Ministry of Science's defeat, Membros began working for Baron Karza as his supreme interrogator. When Karza began his invasion of Earth, Membros led a squad in charge of pursuing and capturing the Micronauts dead or alive. After his team shot down the Heliopolis, Membros had them set down so they could collect their targets. Though the other Micronauts were knocked out by the crash, Acroyear had managed to remain conscious and gave his attackers what for until Membros knocked him out with an electric shock. As he gave his team the order to bring the Micronauts to their ship, Membros commented that he looked forward to resuming his interrogation of Oziron.
After their capture, Membros visited Oziron, Phenolo-Phi, and Biotron in their cell, poking fun at the state of disrepair Biotron had fallen into. Pleased that Oz remembered him from their first meeting, Membros informed him of the outcome of the war between the Ministries of Science and Defense. He then taunted the three of them with the information that Acroyear was currently being painfully "reconditioned" and that he believed the unaccounted for Larissa and Microtron perished in the Heliopolis's crash and subsequent explosion. After finally getting his long awaited session with Oz (during which he merely tortured the Pharoid for two hours without ever asking a single question), Membros learned he was wrong to assume the missing two Micronauts had met their end when they stormed his office after breaking their comrades out of prison.