During the Cosmo Babylonia Wars, Crossbone Vanguard ace pilot Zabine Chareux, known for his distinctive eye patch, led the Black Vanguard Squadron against the Federation, developing a bitter rivalry with the Gundam F91 pilot Seabook Arno. After the collapse of Cosmo Babylonia, Zabine continued to serve with the Crossbone Vanguard, which had been reformed under Berah Ronah.
Needless to say, Zabine never really got along with Seabook, who had also joined the Vanguard under the alias Kincade Nau; the only reason he put up with Seabook was that he was Berah’s lover. Eventually, his own resentment towards Seabook and Berah, combined with a growing disillusionment with Berah’s leadership, would lead him to turn against the Vanguard and defect to the Jupiter Empire, which he came to admire due to its similarities to the old Cosmo Babylonia.
As the conflict between the Crossbone Vanguard and the Jupiter Empire was about to reach its climax, Zabine would take advantage of the fighting to finally settle matters with Seabook once and for all.