Survival of the Fittest – Season 1 Episode 09 Survival of the Fittest Original Air Date: March 3, 2001. Away from the institute, the X-Men are thrown in a survival training boot camp with the Brotherhood. While the young mutants are out of the picture, Mystique frees Cain Marko, the unstoppable Juggernaut, from his imprisonment in hopes of gaining access to Xavier's School. However, cooperation isn't on Juggernaut's mind when he takes off on a rampage of revenge against his half-brother.