Mokuba Kaiba is Seto Kaiba's younger brother. His soul gets captured by Pegasus and Seto has to save him, but ends up having Yugi save them both. Mokuba really likes Yugi as a friend but Seto doesn't and doesn't like the fact that Mokuba likes Yugi.
Mokuba, like his brother really likes duel monsters, but doesn't play. When he is taken to Pegasus' castle he escapes to duel Yugi because if he takes Yugi out then there is no way that Pegasus can take over his older brother's company. He ends up trying to steal Yugi's star chips but doesn't succed. He thinks that the cards are all about power like his brother until Yugi shows him that its about heart.
