Iska and Unit 907 have defeated one of the Eight Great Apostles, Luclezeus, and arrived at the Imperial capital. There they meet Lord Yunmelngen, who asks Sisbell to use her astral power to help uncover the truth behind the tragedy that transpired a hundred years ago. At long last, the mystery behind the birth of the Founder Nebulis, of Lord Yunmelngen, and of the Black Steel Gladiator, Crossweil is revealed!