Ben 10 Omniverse: Season 8, Episode 6

8 - 6: Final Countdown

While Rook is stuck on graveyard shift at Plumber HQ, his sensei Kundo returns as a cyborg to purge the galaxy of technological influence. Ben and Max take a massive Plumber squadron to stop Yeta, a female Shockquach alien, from continuing her criminal destruction. They later find HQ on lockdown because of Kundo and try to break into the base to give Rook back up. Fistina, the only prisoner, is deputized by Rook so as to help defeat Kundo. Following Kundo's defeat, Rook is effectively promoted to Majestor and Fistina is allowed to go to the academy following her time served.