In Episode 16, " Vrak is Back (1) " , the stakes reach a boiling point as one of the series' most calculated villains returns to reclaim his birthright after the demise of his brother, Prince Vekar . The Master Plan: Earth on the Brink

: Vrak reveals he has been holding Robo Knight captive and has reprogrammed him into Dark Robo Knight.

In a classic Vrak move, he tricks the Rangers into doing his dirty work. He sends his henchman, , to fight the Rangers. When the Rangers use their Sea Brothers power to destroy him, Vrak reveals that Tresnag was a "cipher" designed to absorb their attack energy. That very energy is what powers the second giant drill, leaving the Rangers in a state of despair as they realize they’ve helped Vrak get one step closer to checkmate .

: By draining Orion, Vrak turns the Rangers’ Legendary Keys to stone and disables their Super Mega Mode . This forces the team to revert to their original Megaforce forms and arsenal, including the Gosei Great Megazord . Dark Robo Knight Returns