Kai, one of the main protagonists, appears in the end of the very first episode of the show; at the time Kai is the team captain of the Blade Sharks, as well as the Beyblade world champion. Tyson Granger, another protagonist of Beyblade and Kai meet after one of Kai's 'underlings', Carlos, loses to him. Kai defeats Tyson as easily as Tyson did Carlos, though he does not use his bit beast for this victory. Later on, Kai kidnaps Tyson's genius friend Kenny, and is challenged by Tyson for his freedom. The fierce battle ends in a tie thanks to Tyson's new bit-beast, Dragoon. Kai releases Kenny anyway and leaves. No further confrontation occurs between Kai and Tyson until the Regional Tournament, in which Kai participates and defeats many of Tyson's friends on the way to the finals, including Max Tate.

In the finals, Kai and Tyson battle a close match but Tyson wins. After the battle the director of the BBA, Mr. Dickenson, offers Kai a position as team captain of the Bladebreakers, due to Kai's position as world champion and his great experience in the sport. Though Kai is unconvinced, his pride pushes him into accepting leadership. The team goes on to win the Asian and American tournaments ; they also defeat the top European team: The Majestics. At this match, Kai plays a significant role, defeating Johnny.

At the World Championship, after visiting Balkov Abbey, Kai begins acting strangely. In a bold step, he leaves the Bladebreakers and joins with his grandfather Voltaire, and his team, the Demolition Boys. Here, Kai reunites with a powerful bit beast he had become enraptured with as a child; the seemingly perfect Black Dranzer. With this new bit beast Kai is able to get the Demolition Boys all the way to the finals. Before these, Kai issues a challenge to his former team, even sending a helicopter to escort them to the frozen Lake Baikal. There, Kai battles Tyson, Ray, and Kenny, overwhelming them all with his power. Just when Tyson's Dragoon blade seems about to be demolished, Max arrives on the scene with his brand new, much stronger Draciel blade. Tyson takes the opportunity to launch Kai's abandoned Dranzer blade, and Dranzer's anger, as well as the combined determination of Ray, Tyson and Max, pushes Kai into realizing the true power of friendship. The ice begins to crack, but Kai, frozen in realization of his pride, refuses to move. It is only after a few words of support from his team that he sheds a tear and allows them to pull him back onto solid ground. Kai then acknowledges his role as leader of a great team and rejoins the Bladebreakers for the championships.

He reveals the profound impact that the encounter upon the ice has had on him when he loses to Spencer of the Demolition Boys. Rather than rail against his loss, he graciously accepts defeat and manages to come out smiling. Proving his new-found team spirit over the last few episodes of the season, Kai offers Ray the words of advice and support needed to ensure the Bladebreakers the win they desperately need, before later helping Tyson to prepare for his final confrontation with Tala, along with the other team captains they have met throughout the season. Although it is not shown in the show, there is proof from BeyBlade: Super Tournament Battle the video game for GameCube, that shows that Kai's actual first beyblade was the Frostic Dranzer.