A Whale of a Ride (1) - S1.E51

Leo and Luna defeat Devack, and he disappears, freeing all the trapped spirits. Ancient Fairy Dragon and Regulus give their thanks to Luna, and becomes cards in her deck. Luna places the Ancient Fairy Dragon card in the control unit, deactivating it. Making sure everyone is safe, Yusei decides to head towards Kalin. Hearing about Devack’s defeat, Roman sways Greiger over to his side, and executes him in order to transform him into a Dark Signer.