The Legionnaries, know also as the Batch SW6 (Legion), were a team of teenagers from the future who astonishly resembled, psysically and with the same memories and personallity to the classic Legion of Super-heroes. They were found in cryogenic stasis chambers property of the Dominion, hidden under the Time Institute in Metropolis, during a dark time when the Earth had fallen under control of the Dominators. After being awakened, they discovered how wrong had things went for mankind and joined the undergrond resistance forces.
Originally they were believed to be clones of the original Legion, who had not lived during the sour times than had worn out the Legion until their disband. They helped to end the control of the Dominators on Earth, but their help was not enough to save Earth from destruction. However they were relevant to keep united the New Earth from falling apart. During this time new members who had never been part of the Legion, joined them. But not even with them could stop the until timestorms than started to erased zones of the universe and time paradoxes impact them.
When Rokk Krinn faced the Time Trapper in his Fortress at the end of time, the Trapper revealed than he was who had created the Batch SW6 when he had split the legionnaires at different moments of time and put them in chronal stasis in those chambers, as divergent lives, freezed from any new experiences.
When the Legionnaires discovered this truth, they reluctantly accepted the word of the Trapper and his help in the middle of the crisis they were facing. They were then merged together in the pocket earth meanwhile the Trapper faced the cause of the destruction of his time. The 30th century would then be reborn after the Zero Hour as the 31st Century.