|“||I am the number 1 ranked Duelist in the country and the favorite to win the Duel Monsters Championship. You wouldn't last two minutes in a Duel against me.||„|
|~ Kaiba flaunting his Dueling skills to Joey.|
|“||Mokuba! Get back!||„|
|~ Kaiba to Mokuba when Alister drew the Seal of Orichalcos.|
Seto Kaiba or just commonly referred to as Kaiba, is one of the two deuteragonists (alongside Joey Wheeler) of the Yu-Gi-Oh! original series and both of its adaptations. He has a younger brother named Mokuba, whom he always shows compassion for, and Priest Seto is his Egyptian incarnate. He is the CEO of Kaibacorp, and aims to become the world's greatest player of Duel Monsters. To accomplish this goal, he must defeat his arch-rival, Yugi Muto. He is the modern-day lookalike reincarnation of Priest Seto himself, the original keeper of Blue-Eyes White Dragon. He seems to like to mock Joey Wheeler, similar to Priest Seto mocking Mahado.
He is voiced by Kenjiro Tsuda in the Japanese version and Eric Stuart, who also voiced Brock in the 4Kids dub of Pokémon, in the English version.
Seto Kaiba does not believe in the supernatural till late season 5 where he sees magic is real. He does not believe in friendship, he prefers to be alone, thinking it makes him stronger, but sometimes he accepts help from some people if it's really necessary. He also has a huge ego and is very arrogant until the end of the anime where he's more humble. He is an anti-hero usually selfish but he helps Yugi and his friends sometimes at defeating common enemies. One of his more redeeming qualities is his care for his little brother Mokuba. He will go to great lengths to save him if he is in danger. Though he hates Yugi and his friends, Kaiba holds a hatred toward those greater than Yugi are both his adopted father, Gozaburo and his archenemy, Zigfried von Schroeder. Kaiba is very intelligent, he has great abilities in business, science and technology, most noticeably programming, hacking and engineering.
As a child, Seto Kaiba was a bright boy, protective of his brother, and mainly selfless. After he and his brother were adopted by Gozaboro Kaiba, he was forced to undergo vicious studying and learning habits to allow him to understand how business works at its best. On Seto's birthday, he was given a 2% share of KaibaCorp (in the English anime, $10 million) and was told that although he could spend the money any way he wished, he must return one hundred times (in the English anime, 10 times) the amount in one year. Seto returned all the money within a single day. He did this by buying 51% shares of a small company that cares for its employees, Seto then made the president buy it back, under threat of it being shut down and leaving the employees jobless. Kaiba will stop at nothing to get his way, going so far as to drive his stepfather to suicide so he could inherit KaibaCorp. He is also seen as a master of all games, but his favorite is Duel Monsters.
Kaiba proves to be an incredibly greedy and sadistic monster with a sociopathic and borderline insane personality; having found out that Yugi's grandfather had the Blue-Eyes White Dragon card, the two dueled for the intensely rare card, of which there are only four. As it turns out, Kaiba already has the other three of them and does not even need a fourth card. When Kaiba wins with these three, he realizes this and tears his prize to pieces, breaking Sugoroku Muto's heart. Yami Yugi takes over and duels Kaiba, and manages to win.
Yugi then uses his powers to put Kaiba under a Penalty Game, in this form, he traps Kaiba in an illusion of the duel monsters world, where Kaiba is continuously eaten by the monsters. This gives Kaiba nightmares from onward, but his resolve is only strengthened. He constructs an entire event at a theme park, in order to plot Yugi's death, as well as his friends. Kaiba kidnaps Yugi's grandfather in order to get Yugi to come, and destroys the Blue Eyes White Dragon he won from him. In the final battle with him, Kaiba recreates the "shadow game" that Yugi made, with a large glass box that will set of an illusion on the person who loses. Kaiba notes that the shock almost killed Yugi's grandfather. During the set of events that follow, Kaiba nearly kills Honda, as well as his own brother Mokuba.
Kaiba ends up losing the match when Yugi summons Sealed (Exodia in the 4Kids dub), the rarest, and most difficult to summon card in the whole game. Yugi places Kaiba under another penalty game, this one being Mind Crush, a penalty that ultimately leaves Kaiba himself comatose. But with Dark Yugi later telling Mokuba that Seto is repairing his shattered heart so that the next time he emerges, Seto will not make any mistakes.
From here, Kaiba became more of an anti-hero than a villain, and usually does nothing worse than trying to get in Yugi's way or make fun of Jonouchi. In the majority of the Duelist Kingdom arc, he was out to save his brother Mokuba, who was kidnapped by Pegasus J. Crawford, but was sealed inside a card after being defeated by him. After Pegasus was defeated, and Mokuba, Sugoroku, and himself released, Seto set out to become better than Yugi, and collect all three Egyptian God Cards. He received one, the Giant God Soldier of Obelisk, from Ishizu Ishtar, and created a tournament called Battle City so he could get the other two (making it a rule for the loser to fork over their rarest card to the winner). Here, he was counting on the Ghouls entering (as they possess the two God Cards), however, they kidnapped Mokuba (though he escaped) and forced Yugi and Jonouchi to duel each other to the death, but they both survived. He showed his ruthless side again during the Dark Games, where he was more concerned about seeing the Egyptian Gods in action than about the health of the duelists, which was several times in life-threatening danger.
After the quarterfinals, the tournament was interrupted (IN THE ANIME ONLY) when Kaiba, Yugi, Jonouchi, Anzu, Honda, Shizuka, and Ryuji Otogi entered the virtual world to face Noah and the Big Five, with Kaiba defeating Lector, and later his evil stepfather Gozaburo, who perished when the virtual world was destroyed.
Kaiba lost to Yugi in the semifinals, and with the duel, the Giant God Soldier Obelisk. After Yugi defeated Marik in the final round, Kaiba, as a sore loser, blew up the duel tower but warns every ones to get off the island, escaping with Mokuba aboard his private jet they managed to escape the explosion. However, he was forced to fight alongside Yugi again when Dartz attempted to take everyone's souls for the Oreichalcos. He defeated Dartz's henchman Amelda in a duel, causing Amelda's soul to be taken. He and Dark Yugi dueled together against Dartz. Kaiba lost the duel and his soul, but Yami defeated Dartz, releasing Kaiba's soul from the Oreichalcos.
From here, Kaiba never did anything even remotely evil. He hosted a tournament in which he did not enter, and in which the winner would face Yugi in the final round. His enemy, Zigfried von Schroider, attempted to use his younger brother Leonhart to erase all of Kaiba's data. But luckily, Kaiba had it all saved on backup, and this was foiled. Kaiba later entered the RPG to help Yugi fight against Zorc, realizing for the first time that everything unusual (such as Hell) was real and not just a trick (as he had thought for most of the show). He witnessed Yugi's duel against Dark Yugi and finally came to accept that Yugi is the king of games.
In the video game Yu-Gi-Oh! The Falsebound Kingdom, he is a playable protagonist with his own campaign, he appears as a boss in both Yugi's and Jonouchi's campaign. He uses all three Blue-Eyes White Dragons and has Polymerization to fuse them into the Blue-Eyes Ultimate Dragon. In Yugi's campaign, he appears in the level "Face-Off" to which he is forced to duel Yugi under Scott Irvine's orders. After he is defeated, he explains that he did it in order to rescue Mokuba to which the two then work together to take down Irvine. In Joey's campaign, which is a prequel, he appears as his role working for the emperor and sent to destroy Jonouchi's resistance group. Though Jonouchi wins the duel, Kaiba succeeds in destroying his resistance and they must separate and join up with Yugi.
- Because Mokuba is the only one to call him by his first name Seto, some fans forget it; as everyone else just refers to him by surname. Even merchandise only refers to him solely as Kaiba.
- Kaiba's deck focuses on supporting his Blue-Eyes White Dragon, while stalling with the XYZ series.
- Despite originally being shown to be Yugi's classmate, Kaiba never shows up later in the series during school scenes. It's possible he was allowed to do school through correspondence, or Kaiba simply used his connections to "graduate" early as he was already too smart for average schools like Domino High.