Mokuba Kaiba

Mokuba Kaiba (海馬 モクバ, Kaiba Mokuba?) is a fictional character in the Manga and Anime series Yu-Gi-Oh!. Mokuba is Seto Kaiba's younger brother. In the manga, Mokuba is characterized as a spoiled brat, always trying to trick Yugi Mutou to get back at him for defeating his older brother. In the first series of the manga Mokuba tries to defeat Yugi before Kaiba has a chance and challenges Katsuya Jonouchi (Joey Wheeler in the English anime) and Yugi to a Roulette of Death and poisons Jonouchi. Yugi eventually wins and saves Jonouchi. Mokuba is another good game player who specializes in Capsule Monster Chess ("Capmon"), but is not as good of a gamer as his brother. He is so committed to avenging his brother's humiliation, he uses several extreme measures, such as having his friends brandish a machine gun, a knife, and a stun gun in one manga chapter to coerce Yugi to play "Capmon" with him. In the second series of the anime, Mokuba is eternally devoted to his brother Seto Kaiba and is constantly by his side. He is more naive and good-natured, the antithesis of his scathing, cynnical brother.

In the manga, at a young age, Mokuba and Seto were orphaned (their actual surnames unknown). Seto's mother died after Mokuba was born, and their father died in an accident when Seto was eight. Their relatives used up their inheritance and left them at the orphanage. When the former head of Kaiba Corporation, Gozaburo Kaiba, arrived at the orphanage to perform a publicity stunt, Seto saw the chance to challenge him to a game of chess, with Gozaburo forced to adopt Seto and Mokuba should he win. Mokuba was five at the time, while Seto was ten in the manga and Japanese anime, and in the English Duel Monsters anime he was twelve. Seto had won by cheating in the manga. In the anime, he won by studying Gozaburo's chess methods. Gozaburo forced Seto into a rigorous accelerated school program. Six years later, Seto Kaiba took over his father's company. In the manga and the second series of the original Japanese anime, Gozaburo, provoked by Seto, committed suicide. In the first series, Seto electrocutes Gozaburo after Seto takes over the company. In the English anime, he "ran away".

In the second series anime, Seto was bright and intelligent, which led to many prospective parents wanting to adopt him, Seto swore to protect his brother at all costs, and wanted Mokuba adopted with him, which all had refused. Gozaburo also had an ulterior motive: he wanted to adopt Seto because he was bright enough to be motivation for his own son, Noah Kaiba, to do better so that Noah could inherit KaibaCorp. With Noah's untimely death, however, Gozaburo focused his energies to Seto. Gozaburo asked Seto to return ten times of an amount of money given to him. Seto did so within a day and took over his father's company. In the Battle City arc of Yu-Gi-Oh!, Mokuba is the Battle City commissioner (he called himself that), calling violations and penalties when needed.

In the original Japanese version of the Yu-Gi-Oh! manga, Mokuba tends to omit honorifics when referring to people other than his older brother. He also has a habit of calling Jonouchi Jōnouchi no yarō; (that bastard Jonouchi). Mokuba politely refers to his older brother as nii-sama (honorable older brother). In the second series Yu-Gi-Oh! anime (Yu-Gi-Oh! Duel Monsters), Mokuba is a kind-hearted boy who is naïve to the ways of the world. He succeeds in befriending Yugi and his friends; his brother does not approve of this. Mokuba does not duel in the second series anime. He only duels in the first series and manga. Mokuba has a unlucky streak of being kidnapped by Seto's enemies forcing Seto to show his kinder side and rescue him.