98 years prior, a soldier named Jan Sauer died when he committed suicide after the deaths of his wife and stepson at the hands of a terrorist. However, because of the Life Recycling Act, his body was reconfigured into a cyborg by Ziggurat Industries, and was given the official title of Ziggurat-8. Like Realians, Ziggurat-8 had little in human rights (since he wasn't considered 'human' himself), and had suffered some of the discrimination that both cyborgs and Realians had to endure.

His latest mission for the Galaxy Federation was to retrieve the 100-series observational Realian prototype, MOMO, from the clutches of U-TIC. However, once he did, MOMO told him that she didn't like the designation he had and nicknamed him 'Ziggy', which stuck. Ziggy then took MOMO away to the Elsa Van Brabant, where they hoped to head to Second Militia without incident.

That is, until the Elsa had encountered KOS-MOS, who was floating in space after the Woglinde attack. After 'persuading' Captain Matthews to take in the survivors Allen Ridgley, Lt. Louis Virgil and Shion Uzuki, Ziggy decided to take on KOS-MOS, seeing her and her friends as threats to the mission. After a brief battle (which was broken up by MOMO and Shion), Ziggy learned of the groups' travails... and had taken them up as his friends – something the cyborg had little of.

(source: Absolute Anime)