Yu-Gi-Oh! Duel 26: "Russian Roulette"
Kaiba's chauffeur is one of the Kaiba family servants.
Under Seto Kaiba's instructions, the chauffeur collected Yugi Mutou and Katsuya Jonouchi to bring them to Kaiba's mansion. As they wondered why Seto wanted to see them and noted how Seto had been absent from school lately, the chauffeur explains that Seto is president of KaibaCorp and has been working on an important project.