Seto Kaiba is a main character in Super Smash Bros. Crossover starting with Season 17. While Kaiba didn't appear in Season 16, one of his Blue-Eyes White Dragons were stolen by Nightshroud. In Season 17, Zane Truesdale returned the stolen Blue-Eyes to him, and told him of the events of Season 16 (more specifically, the invasion of Gundalia). While it is unknown if Kaiba really believed this, he decides to deliver a box of Duel Monsters cards and multiple Duel Disks around the universe and hosts an intergalactic Duel Monsters tournament. Later, Kaiba tracks down Ganondorf since his computers indicated that Ganondorf was the only competitor without a Duel Disk, and gives him one. Kaiba notices Ganondorf address Samus Aran (who is being possessed by Nightshroud) as Nightshroud, and soon realizes this is the same being who stole one of his Blue-Eyes. However, Kaiba is grabbed from the face by Nightshroud, who proceeds to possess him due to him being the host of the tournament. Kaiba is later freed from Nightshroud's influence by Blue-Eyes White Dragon. During the second half of Season 17, Kaiba suspends his tournament and warns everyone to watch out for Samus and Yami Bakura. After Zorc Necrophades is defeated, Kaiba tells Naruto Uzumaki and Sasuke Uchiha that they are qualified for the finals of the Duel Monsters tournament and they will duel him and Yugi Muto, with the winners being the champion.
Kaiba's main appearance is based off his appearance from Battle City onward. While being possessed by Nightshroud, Kaiba's eyes are red rather than blue.
Seto Kaiba is very arrogant, but he does care about the children of the world. Kaiba doesn't really believe in magic, but he apparently believed what Zane told him about the invasion of Gundalia, as he delivered a box of Duel Monsters cards and multiple Duel Disks to various worlds to host an intergalactic Duel Monsters tournament. Kaiba has an obsession with Blue-Eyes White Dragon as after his announcement, he called Zane and thanked him for returning the Blue-Eyes that was stolen by Nightshroud, and showed hostility toward Nightshroud when he realized his identity.
Seto Kaiba is one of the best duelists in the world, having only lost once while possessed by Nightshroud.
|Naruto Uzumaki and Sasuke Uchiha||Draw (Tag with Yami Yugi)|
|Yami Bakura||No outcome (Tag with Yami Yugi)|
|Patient Zero||No outcome|
|Samus Aran||Win (Samus forfeited the match)|
- Unlike Nightshroud's other hosts, Kaiba's appearance remained the same, with the exception of his eyes becoming red.