And I shall slay you. . Acnologia (アクノロギア Akunorogia), also known as The Black Dragon (黒龍, Kokuryū), and fearsomely reputed as The Black Dragon in the Book of Apocalypse, is a cataclysmically powerful human being that can take the form of a Dragon that assaulted the Fairy Tail Mages on Tenrou Island in the Year X784. Acnologia (アクノロギア Akunorogia), also known as The Black Dragon (黒龍, Kokuryū), and fearsomely reputed as The Black Dragon in the Book of Apocalypse, is a cataclysmically powerful human being that can take the form of a Dragon that assaulted the Fairy Tail Mages on Tenrou Island in the Year X784.