He was voiced by famous voice actor Oliver Wyman (credited as Pete Zarustica).
Siegfried Von Schroider's family has a long feud with Kaiba's, which started when they were kids, as Siegfried's father's business partner Gozaburo Kaiba kept stealing business deals under his nose, leading to his premature retirement. When Siegfried took over the family business and decided to turn his company into the gaming business, he discovered that Kaiba did so with his own years prior, unintenionally robbing him of business opportunities. Finally, Siegfried chose to work on a device able to project Duel Monster cards, only to to find out that Kaiba came up with a better one, finally making him snap.
Grand Championship Tournament
As revenge, Siegfried attempted to sabotage Kaiba's Grand Championship at Kaiba Corp. First, he set a computer to trap everyone inside, but the computer was defeated by Yugi Muto. Siegfried entered the tournament as Sieg Lloyd, and easily defeated Insector Haga and Dinosaur Ryuzaki using his Valkyries Cards. He then dueled Katsuya Jonouchi and won.
As he was about to face his younger brother Leonhart in the final round, Kaiba realized his true identity and dueled him. Kaiba won, but Siegfried still had his main plan up his sleeve while Leonhart was dueling Yugi in the finals, Siegfried had him play a card called the Golden Castle of Stromberg, which was infected with a virus that deleted Kaiba's data. Leonhart, who had no desire to willingly participate in evil plans, and Yugi were able to stop it during their duel. After Yugi defeated Leon, Kaiba revealed that all his information was saved on a backup, and was never lost. Siegfried was utterly defeated, and Leonhart convinced him to make his corporation as good as Kaiba's without doing anything evil.
- Zigfried's designs for holographic Dueling is near identical to the Duel Boxes used in the original manga.
- In the Japanese version of the anime, when Zigfried plays "Ride of the Valkyries", the actual Wagner melody Ride of the Valkyries can be heard.
- Zigfried bears certain physical similarities with Halldor from Yu-Gi-Oh! 5Ds. Both used Norse Mythology-based Decks, are in opposition to their respective show's main characters, until they realized the error of their ways and acknowledged their former enemies as comrades.
- Zigfried and Noah Kaiba are the only major villains in the second series anime that have no awareness of Yami Yugi's existence.
- He is also the only main antagonist of an arc who never Duels Yami Yugi, rather Zigfried viewed Kaiba as his primary enemy. He is also the only main antagonist whose goals and methods are totally mundane (even Noah had access to advanced technology).