Warning: The following contains SPOILERS for Young Justice season 4, episode 9, «Odnu!»
A scene that played out under the closing credits of one Young Justice season 4 episode seemed to hint at a great war in space that decimated the ranks of the Legion of Superheroes. This apparently prompted the survivors to travel back in time to prevent the war from happening. The Legion's presence in Young Justice season 4 has yet to be fully explained, but it had been suggested they were trying to avert
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