Seto Kaiba, owner and president of Kaiba Corporation, is no one's fool. Inheriting the business (and his cold attitude) from his late foster father, Kaiba has become one of the youngest corporate sensations in history. Mind you, the guy is still very young and yet he runs his own world-recognized tech corporation. Kaiba is himself a skilled computer user and a genius designer, making a number of technological leaps, mostly in the realm of entertainment. His Kaiba Land amusement park is noted for its innovative holographic Duel Monsters dueling arenas.

Why the emphasis on Duel Monsters? Because the only passion he has greater than technology or business is the Duel. He's the reigning World Champion and one of the most dreaded opponents one can ever face. He steps into any duel with perhaps the most serious and determined demeanor anyone can show. His Dueling Deck is a fearsome collection of powerful monsters, choice cards from his own vast collection. The crown jewels of his Deck are his three Blue-Eyes White Dragons: some of the most powerful monsters one can summon under normal circumstances. He has the only three remaining in existence (there was a fourth belonging to Solomon Moto [Sugoroku Mutou], but Kaiba tore it up personally).

But then, his business and passion for the Duel are put to the test. His first loss comes against Yugi (when Yugi managed to complete Exodia the Forbidden One that one time), and Yami Yugi's Mind Crush liberates the real Kaiba from the more wicked part of him that had been developing. The Big 5 of Kaiba Corp then begin an attempt to sell off the business to Maximillion Pegasus' Industrial Illusions. To help in that task, his only remaining family, his younger brother Mokuba, is kidnapped and taken to the Duelist Kingdom. So Kaiba sets off after Pegasus and Mokuba, armed with his latest invention: the Duel Discs. The Duel Discs are in essence a portable dueling system, allowing a duel anywhere, anytime (the Duel Discs are later released to the public to set the stage for Battle City).

In the process, Kaiba comes to Yugi's aid (if only to hurt Pegasus). But when Pegasus forces Kaiba's hand by sealing Mokuba's soul in a card, Kaiba is forced to duel his nemesis again. Despite his best techniques, he only manages to beat Yugi by putting his life on the line, a move Yugi was unable to accept. However, Pegasus would in turn unleash his own powers to beat Kaiba in a subsequent Duel and seal his soul in a card as well. Yugi duels and defeats Pegasus and wins the Kaiba brothers' freedom, although his original intention to fight was to save his grandpa, Solomon Moto.

Kaiba then turns his attention to his own corporation, who he now knows is trying to undermine him. He is trapped in a virtual reality game inspired by Duel Monsters, and once again, it's Yugi who helps him to escape. Despite these assists, Yugi and Kaiba consider each other to be heated rivals. There is still a long, hard road ahead for the cold, calculating duelist, especially when Ishizu invites him to an Egyptian exhibit and reveals to him the strings of destiny that are wound between him and Yugi stemming from 5,000 years in the past. Kaiba is to play a significant role in what is quickly becoming the grandest, most dangerous game of all.