Reginald Kastle's History
Originally born as Nash, he was once the emperor of the United Lands of the Poseidon Ocean alongside his sister, Marin and was well-loved by his people. One day, his kingdom was attacked by Vector, who led a fleet of ships and several "Gorgonic Guardians" to lay waste to it and loot it.[34] Nash ordered a counterattack, arming his soldiers with mirror shields which turned the gorgons' abilities against them. Vector performed a blood sacrifice in response, calling forth the ocean god, Abyss, turning the tide of the battle again. Marin rode up to Abyss and was grabbed by him. Despite the intervention of Nash's friend, a knight named Dumon, Marin did not want to be saved and sacrificed herself to call forth another god to purify Abyss.[35]
After Marin's funeral, Nash declared an attack on Vector's kingdom in retribution, as the latter has fled with the god turned to Nash's side. Once they got to a town ravaged by Vector's army, Nash noticed a little girl crying, who strongly resembled Marin.[36] Nash took the young girl, Iris, under his care and wondered if she was his deceased sister's reincarnation or if she was sent by Marin herself. As Nash and his army pursued Vector, Nash grew close to Iris and planned to confront Vector by himself once the battle started. On war front, Nash followed Vector to a secret tunnel in what would eventually become a Number ruins, where Vector challenged him to a Shadow Game. Per the Duel's rules, the more monsters of either ruler that were sent to the Graveyard, the more soldiers their army would lose. Though Nash was victorious, his entire army was lost due to Vector's mill strategy. Their souls were sent to the Barian World.[37] Vector barely survived and limped back to his own country, prompting Nash to follow him. There, he found Vector had killed all of his own people.[31] After defeating him a second time, he witnessed Vector being dragged into the afterlife by the people he murdered.[24] With all his comrades and loved ones sent to Barian World, Nash gave up his live and willingly became a Barian.[38] Although Don Thousand never manipulated him directly like he did the other emperors, he did influence Nash's actions by making Marin sacrifice herself to instigate the war against Vector and by orchestrating the Shadow Duel between the two adversaries.
Nash's and Marin's souls being sent to Earth in the bodies of Reginald and Rio.
An unknown number of years later, Don Thousand reincarnated both he and his sister as two of the Seven Barian Emperors, as their souls were each connected to a Mythyrian "Number" card, which had sealed Thousand's power.[39] Nash then became the leader of the Seven Barian Emperors, much to Vector's disdain (also having been reborn as a Barian Emperor). After Nash had annoyed him enough to score 100,000,000 (1,000,000 in the dub) points, Vector enacted his revenge by taking Marin hostage. When Nash intervened, Vector used "Giant Sky Sword" to open a bottomless rift and then pushed Marin from the cliff, forcing Nash to dive after her, only for the two to be sucked into the rift. The two were rescued by Abyss, who informed them that he would send them to the Human World without their memories, where their souls were then revived in the bodies of Reginald and Rio Kastle, both who were pronounced dead in a car accident.[40] While Vector believed them dead[35], Dumon believed they had simply disappeared and assumed leadership of the group from them in the interim, waiting for their return.[41]
Current life
Reginald and Rio as children.
At another time, Reginald and Rio visited a theme park. While there, Rio obtained a pair of matching rings they could wear together. Reginald refused her offer to wear one, and she walked off in anger, calling him an "idiot" and tossing the rings to the ground.[12]
Reginald surrounded by pressure.
Years later, Rio was critically injured in a fire, while Reginald became a well-known and popular Duelist within the National Duel Circuit. After making it to the final round, the pressure got to Reginald's head, causing him to become desperate because he wanted to win to support Rio.[42] By this point, he began wearing both of the rings that Rio had obtained when they were children, in order to remind him of their bond.[12] While preparing for the finals in the waiting room, he noticed that his opponent, Quattro left and dropped his Deck. While not intentional, Reginald's desperation got the better of him and ultimately looked at the visible cards on the floor. Midway through his Duel, while neither Duelist had a visible advantage, Reginald was disqualified and the match was canceled, as he was discovered to have looked at his opponent's cards. This also caused him to be permanently banned from the Duel Circuit.[19]
Reginald gets banned before he makes his winning move.
After this ban, Reginald became a delinquent and began to steal the Decks of his opponents once he beat them. It is known by most students within Heartland Academy that Reginald was not only a skilled Duelist, but also a bully.[1] He obtained the nickname "Shark", due to the fact that he used an ocean-themed Deck and because he ripped his opponents' Decks out of their hands swiftly and with malice. Despite Shark's actions, Yuma Tsukumo defended him, as he believes that everyone has done something in their past which they regret.[19]
