From DC Database
Pre-Zero Hour is the possible future in which the original incarnation of the Legion of Super-Heroes was active. Originally a function of Earth-One, it survived past the Crisis on Infinite Earths into further continuity, and even went through several other iterations in which the same characters remained active, such as the Mordruverse and Glorithverse. It was seemingly destroyed during the events of Zero Hour, and remained out of continuity for 13 years, in which two other individual Legion incarnations both separately acted in the 31st Century. After Infinite Crisis, this future returned, and its Legionnaires and other characters have begun to interact with the heroes of the 21st Century once again. This new version branches off from the original continuity at around the time of the Crisis on Infinite Earths, essentially only retaining its Earth-One history, to an unclear extent.
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