Yu-Gi-Oh! Duel Monsters

Sinister Secrets (Part 1 of 3) (5x12)

Air date: Mar 17, 2004

With Kaiba's hacker trouble out of the way, it is time for the promised event: Yugi, the King of Games vs. Leon. However, things do not seem as peaceful as they are supposed to be. As Leon progresses up the stairs to the final duel of the event, Zigfried catches his eye and hands him a card with a picture of a golden castle on it, saying it will prove useful. Taking it, Leon begins his awaited duel. However, during the duel, one of Kaiba's men comes up and gives Kaiba some news that unsettles everyone present: Leon and Zigfried are brothers! However, Leon is dueling to help his brother fulfill their mission: destroy Kaiba Corp and advertise their own company.