Leon plays the card Golden Castle of Stromberg on his duel disk, which the Kaiba brothers say shouldn't be possible as the duel disk prohibits banned or fake cards from being played on them, with Zigfried revealing that he hacked into the system to allow the duel disk to play the card. However, this contradicts the events of Battle City, where Seeker's Exodia cards and many of the cards Odion and Marik gave Joey activate like normal, when they were stated to be fake and banned, respectively. The English dub tries to fix this by changing Yugi's line about Seeker's cards being fake into instead being real cards but marked with invisible ink, though there's still no explanation for how Joey managed to use banned cards on the duel disk while Marik brainwashed him into dueling Yugi.