Reginald Kastle

Reginald Kastle, known as Ryoga Kamishiro in the manga and Japanese version and nicknamed "Shark" in all versions, is one of the main characters in Yu-Gi-Oh! ZEXAL. He is one of Yuma Tsukumo's close friends and rivals. He was originally an arrogant and callous person, but has grown quite humble.

Appearance
Reginald has dark blue eyes, pale skin and dark purple hair, which resembles tentacles hanging down, referencing his Deck theme of aquatic creatures. His accessories include a grey, shark tooth-shaped pendant, and two grey rings on his right hand, but he later gives one to Rio Kastle. He also owns a grey and green Duel Gazer with a red lens and a yellow spike as well as a blue D-Pad.

His attire includes a dark purple jacket over a maroon shirt and dark blue pants with white, green-gems shoes. When in his school attire, he wears a white shirt with green-lined sleeves, tie and a collar. During his National Duel Circuit days, Reginald wore a white top with a purple waist coat and his usual dark pants.

Personality
After being disqualified from the National Duel Circuit, Shark became bitter and uncaring, the way he held himself at the beginning of the series. Cold and malicious, Shark flaunts his power by taking the Decks of the people he defeats, making them squirm in the process, such as when he defeated Bronk Stone. When he became possessed by the "Numbers", he became quite violent, destroying the scenery surrounding him throughout the Duel.

However, he does have some honor, as he returned Bronk's Deck upon losing to Yuma as he promised and keeping all the Decks he'd stolen from people completely intact. His defeat to Yuma seems to have humbled him in a way - he is no longer overly cruel to people, as shown when he returns Yuma's pendant after winning an Ante Duel with it at stake. He also seems to put more faith in bonds and friendship, shown by his willingness to form a team with Yuma during the Tag Duel with Scorch and Chills. He further entrusts Yuma with a card that would allow them to win the Duel. Reginald also tries to rescue Emperor's Key from Kite Tenjo and Orbital 7 when it is stolen, clearly stating that he sees Yuma as his friend. In the Duel with Kite, Shark remembers Yuma, and that Yuma would never give up.

Reginald's friendship with Yuma has also helped him in handling the "Numbers" cards. When "Number 17: Leviathan Dragon" came in contact with him, it easily took hold of him. However, he was able to fight off the influence of "Number 32: Shark Drake" because of his bond with Yuma, making him the first known person to be able to resist the influence of the "Numbers" without a special item or power. Despite being able to initially resist the influence, Vetrix said that it did infect him and it will amplify his darkness caused by his desire to take revenge against Quattro. However, after a Duel with Yuma, and seeing his bumbling antics, the darkness had disappeared.

Reginald holds an intense hatred towards Quattro for setting him up to be disqualified and implying that he hurt his sister intentionally. After learning this from Quattro himself, he entered World Duel Carnival and became more cold and more brutal to any Duelist he challenges, even considering Yuma his enemy. After taking his anger out on Yuma in a Duel, he realized what he was doing was wrong and called off the match, with him smiling saying he would see Yuma in the finals.

Reginald can be classified as a typical loner, being indifferent and cool about most things, usually sporting a stoic face or scowl. He prefers to be alone and doesn't follow a crowd, as his encounters with Yuma and others are often brief before he walks off. He also has displayed little interest in school, having had stopped going to Heartland Middle School after his loss to Yuma. However, he still skipped class regardless when he decided to come back and would idly spend his time to the school's roof, but is said to be good at studying. Despite Shark's aloof and cold nature, many students at school respect his Dueling skills and is secretly popular with female students. Despite Reginald's high standard at school, his sister mentions that he is still feared and unlike by some students. Reginald is shown to have a soft side, but has only shown it to two people so far - his sister, Rio Kastle, and his friend, Yuma. Regardless of this, he can be insensitive and cold to both, causing fighting and bickering between them.

Abilities
After the Duel against Vector, Shark gained the ability to see Astral. Shark is also capable of performing Chaos Xyz Evolution with "Number 32: Shark Drake", acquiring a purple aura while doing so.

History
As children, Reginald and his sister 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.

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. 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. 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 canceled, as he was found out to have looked at his opponent's cards. This also caused him to be permanently banned from the Duel Circuit.



After this ban, Reginald turned into a delinquent and began to steal the Decks of his opponents once he beat them. It is known by most students within Heartland Middle School that Reginald was not only a skilled Duelist, but also a bully. 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 Reginald's actions, Yuma Tsukumo defended him, as he believes that everyone has done something in their past which they regret.

Pre-World Duel Carnival
Shark defeated opponents at his school, taking their Decks after they lost. After defeating Bronk Stone, he met Yuma Tsukumo, who attempted to defend Bronk. When asked what his most important thing was, Yuma told him it was his pendant. Shark ripped the pendent from his neck and threw it away. Shark challenged him to a match, with both Yuma's and Bronk's Decks on the line. Yuma accepted.



They Dueled in the city square, with Shark quickly gaining an advantage with "Big Jaws" and "Aqua Jet". He cornered Yuma, but then the "Numbers" were released from the door. Shark was possessed by "Number 17: Leviathan Dragon", which he proceeded to Xyz Summon. As the Duel progressed, Shark began to toy with Yuma, taking his Life Points down to a small fraction. However, Yuma managed to come out of this with the help of Astral, and managed to defeat Shark with his "Number 39: Utopia" at 5000 ATK, which knocked Shark out. When Shark awoke, he gave Yuma Bronk's Deck, keeping his promise. Shark said that Yuma was different than everyone that he has faced before and walked off without another word (in the dub, Shark says "You may have a point till then, Yuma").

Sometime after the Duel, words of Shark's defeat spread around school and his reputation dropped. Eventually, he stopped going to school and also quit Dueling, and was taken in by a gang led by Scorch and Chills, who hung out at an abandoned arcade. One night, Shark was riding on his motorcycle, and stopped after seeing Yuma, staring at him before riding off. One day, while Yuma was late to school, Shark drove across a road on his motorcycle and nearly hit Yuma. After Yuma is belittled by his friends who believe that his victories over Shark and Flip were just because of his "Numbers", he decided to find Shark and challenge him to a rematch, without using the help of Astral or his Numbers. When Scorch and Chills nearly hurt Yuma and his friends, but Shark told them to stop by saying he knows them. After the gang let Yuma go, he challenged Shark, he refused to Duel as his previous loss to Yuma caused him to give up Dueling. Yuma proceeded to chase Shark and annoy him by requesting a Duel until he accepted, Yuma bet Emperor's Key on the result. Yuma did not use his "Numbers" and Shark told him to do so, believing a victory over Yuma without "Numbers" would be meaningless. Yuma Summoned "Utopia", which Shark weakened with "Friller Rabca". This let "Black Ray Lancer" negate its effects and destroy it, which impressed Astral. Shark won with a direct attack from "Submersible Carrier Aero Shark". Shark took the Emperor's Key, but threw it on the ground as he walked off after he remember what Yuma said about being friends. Before driving away, Shark told Yuma that Scorch and Chills gives him a place to belong and told him not be bother him again.

Shark soon overheard Scorch and Chills' plot of raiding the Heartland museum in hope of trying to steal a valuable Deck containing "Chaos End Ruler -Ruler of the Beginning and the End-". He also shocked to discovered that both thugs were possessed by "Numbers". When Chills and Scorch found Shark listening on their plan, he was forced to go along with them, even though he knew this plan was dangerous. Before going, he tells another gang member, Weasel, to run so he doesn't become involved in the dangerous raid, but Weasel went and warned Yuma of the situation instead. Upon arriving at the museum, they found Yuma standing in their way, not allowing them to pass without beating him in a Duel first. He was shocked when Yuma bet his "Number 39: Utopia" on the Duel. Shark warned Yuma not to be concerned for him, but Yuma said he won't leave him alone to rob the Deck. Yuma also pointed out that Scorch and Chills were using him, and that their hideout is not a place for him and insisted that he and Shark were comrades. Shark then decided to Duel with Yuma against Scorch and Chills in a 2-on-2 Tag Duel. On his first move, he Xyz Summoned "Submersible Carrier Aero Shark" and managed to deal effect damage to Scorch. Scorch Xyz Summoned "Number 61: Volcasaurus" and activated its effect, which destroyed "Submersible Carrier Aero Shark" and dealt Shark damage equal to the ATK of "Aero Shark".



Having all their moves countered and with the appearance of "Number 19: Freezerdon", which gave "Volcasaurus" its Overlay Units back, Shark and Yuma were pushed into a corner. After Summoning "Utopia" and having it rendered unable to attack by Chills' "Avalanche", Yuma used its effect to protect Shark from attacks which would have caused Shark to lose. After having "Utopia" and the newly Summoned "Black Ray Lancer" destroyed by "Volcasaurus" (avoiding losing by "Damage Diet"), Shark narrowly avoids losing from a direct attack by using the trap "Final Offering", ending the Battle Phase and giving Yuma "Armored Xyz". After eliminating Chills by forcing him to use his "Compensation Exchange" Trap, which saved "Volcasaurus" by taking damage equal to its ATK, Yuma used "Monster Reborn" to bring back Shark's "Black Ray Lancer" and equip it with the "Armored Xyz" Shark had entrusted to him earlier. It allowed him to give "Lancer" the properties of "Utopia", letting it destroy "Volcasaurus" and attack directly for the win. Afterwards, Shark commented that his card was able to improve Yuma's game, allowing him to keep it before smiling and walking off.



When Tori was trying to ask people about the "Number" cards, she ran into Shark, who told her that she should not get involved with those cards and that they are things that neither of them should understand in detail. One day at school, Shark saw Yuma running through the hallways and was amused by it, commenting how "hot headed" he is. Mr. Kay appeared in front of him, expressing his relief Shark returns to school. He shrugged him off and started to walk away, but stopped after he mentioned how much Shark changed after meeting Yuma. Shark listened to Mr. Kay describing Yuma's "sun-like" power, but keeps his cool when asked his opinion and walks away. On the roof, Shark pondered what Mr. Kay said about Yuma, causing him to smile. Seeing Orbital 7 under a trash can moving underneath him and follow it to the boys' locker room in the gym. Shark witness Orbital 7 attempted to steal the Emperor's Key, but he retrieved it and was chased around the school by the robot.



Just when Orbital 7 was about to kill him with a drill, Kite Tenjo stepped in and called a halt. Shark and Kite both chatted a little about their connection to Yuma, and Shark refused to give Yuma's key to him. After hearing Kite mention the "Numbers" cards, Shark realized he is the "Number Hunter" and then lied to Kite about having a "Number" card, then a Duel is started over the possession over Emperor's Key. Shark was confident about his Deck's new Anti-"Numbers" strategy, which proved effective against Yuma. However, he still wanted to have a "Number", so he planned to steal Kite's "Numbers", but Kite noticed it and used "Number 30: Acid Golem of Destruction" so that its negative effects damage Shark when he steals it. Shark remembered that Yuma would never give up, grasped the key and continued the Duel. When Shark lost, he apologized to Yuma being that he failed to protect the Emperor's Key. Shark's soul was taken by Photon Hand, causing him to he age considerably and become comatose. However, Kite was surprised that the soul didn't possess a "Number" card, but still took his soul when Yuma arrived.



Shark was then maintained in the hospital, being look after by Mr. Kay. After Astral and Yuma draw with Kite in a Duel, he decided to release Shark's soul as he wasn't a "Number" holder. He awoke in the hospital afterwards and was told by Mr. Kay that Yuma saved him.

World Duel Carnival Preliminaries
At the beginning of the World Duel Carnival, he met Yuma, who was panicking because he didn't have a Heart Piece. When he was asked if he would be participating, Shark replied he didn't feel like it. When he drove down the road a bit further, he caught a thrown "Mirror Force" card, the card that Shark associated with his ban from the National Circuit, and it turned out to be Quattro, his opponent in his last pro Duel. Quattro explained he purposely put his Deck where Shark could see it, to get him disqualified.



Quattro also revealed that at that time Shark was not only affected by the pressure of the Finals, but also because of a promise he made to his sister who had an accident and was hospitalized, so he was easily tempted to look at Quattro's Deck,.Quattro also says that maybe his sister's accident was not really a coincidence. Infuriated, Shark demanded to Duel with him again, but Quattro told him to wait for the WDC and tossed him a Heart Piece before departing. Shark then decided to participate after all, to get his rematch with Quattro. He fell into Quattro's trap again as Vetrix told him to coerce Shark into participating in the carnival.

After Kari Tsukumo ordered Yuma to find Charlie McCay, he overheard a crowd cheering. Knowing that it would be a Duel, Yuma ran over to see Shark defeat an unknown Duelist with "Submersible Carrier Aero Shark". After the Duel, Yuma congratulated Shark and asked him why he had decided to enter the WDC. Shark told Yuma about how Quattro had mistreated his sister into the hospital to trick him into being kicked out of the nationals, and now he wants a rematch with Quattro, but after that, he will quit the WDC. Shark then told Yuma not to get involved with him and then wandered off, vanishing from sight of Yuma and Tori.



During the second day of the WDC, after Quattro defeated Bronk and Caswell in a Battle Royal Duel, Shark charged into the area on his motorbike, asking him if he remembered the face of his "Number one fan". Quattro agreed to Duel Shark, but Trey snared Shark with his Duel Anchor, preventing the Duel and saying that Vetrix's orders are absolute. Quattro left in a cloud of dust. In the proceeding Duel, Shark takes control of Trey's "Number" monster, "Number 32: Shark Drake". The "Number" pierced his claws into Shark's chest, but Shark's strong will and connection to Yuma overcame the power of the "Number" and he used it to defeat Trey. Trey told him to keep the card and gave him a Heart Piece, revealing that he himself already had a completed heart. When Shark was about to leave, he once again told Yuma not be get involved with him and rode off. Although he was able to withstand the "Numbers" by remembering his time with Yuma, Shark still wanted his revenge against Quattro for his sister, which allowed "Shark Drake" to infect Shark with a small virus that will amplify that darkness even further. According to Vetrix, this will help them with their plan to use Shark.



When Yuma, Tori, and Astral were looking for Hart Tenjo, Shark saw them from the road above them and stopped. He overheard Yuma calling out for Kite with his D-Gazer, leaving him wondering about situation. During the third day of the WDC, Shark continued to collect Heart Pieces and brutally defeating many Duelists as the power of "Number 32" began to exert its influence on him, fueling his desire for revenge even more. He was confronted by Yuma, who let Shark take his anger out on him in a Duel. Realizing this, Shark eventually came to his senses, with the darkness of the "Number" disappearing and cancelled the Duel. Before he walked off, he told Yuma that they would meet in the finals and gave him a smile.

World Duel Carnival Finals
Shark attended the party that Mr. Heartland threw for the finalists, but he spent the entire time outside the building. He turned to leave when Quattro caught a glimpse of him through a window. Quattro ran to confront him, with Shark turning his back and telling Quattro he will gamble with everything he has in order to defeat him. After that, he left the party and rode off on his motorcycle. The next day, the Duel Coaster began, and Shark easily defeated an opponent with "Jawsman" before seeing Quattro Dueling another Duelist on a nearby track. Quattro told him that he was fighting magnificently, which Shark vowing not to let Quattro get away and chased after him after the latter defeated his own opponent. The chase continued into the underground section of the Duel Coaster, with Shark and Quattro both defeating opponents and taunting one another. Quattro used Shark's anger against him by leading him toward the Magma Field. Since Shark's Deck was composed of WATER monsters, he would be at a disadvantage.



Shark was prepared to counter the field, "Magma Ocean", using cards such as "Plate Salvage" and "Adapting to Adversity". He brought out "Submersible Carrier Aero Shark" on his first turn, inflicting 1200 damage to Quattro before he takes his first turn. Quattro countered with "Number 15: Gimmick Puppet Giant Grinder", which Shark countered with "Number 32: Shark Drake". Vetrix appeared, revealing that he intended to use Shark as an assassin to defeat Dr. Faker. Shark insisted that won't happen, with Vetrix responding that he'll have no choice - he will become Vetrix's puppet. After Quattro managed to Summon "Number 40: Gimmick Puppet of Strings" and using the effect of "Destiny Strings", Quattro attacked Shark a total of eight times. Quattro revealed that he had been manipulated by Vetrix and that Shark's sister was hospitalized as a result of a fire caused by "Flaming Hell Blessing". Shark told him not to act like he was the victim, even if he was used by Vetrix, Quattro was still responsible. Quattro Summoned "Number 88: Gimmick Puppet Destiny Leo", which would let him declare an Automatic Win on his next turn. Vetrix advised Shark to accept "Shark Drake" in order to win and have his revenge. After some resistance, Shark gave in to and was able to create "Number C32: Shark Drake Veiss" as a result. He defeated Quattro, with Vetrix musing that now he and Shark are friends, mocking Yuma's spirit of "kattobingu". Quattro apologized for hurting his sister and urged Shark to defeat his father and save him. Quattro also added that if Shark wanted to hate someone, he should hate Quattro, not Vetrix. Shark watched as Quattro departed through a portal and talked with Yuma. Now wanting revenge against Vetrix as well, Shark told Yuma he would not forgive him if he got in the way. He boarded his Duel Coaster and moved on, having advanced to the semifinals.



After defeating Quattro, Shark exited the area on his motorbike, thinking about what Quattro had told him. While driving down a desolate road, he called out for Vetrix so that he could get his revenge. Vetrix appeared, right in front of Shark's path, which Shark tried to stop his bike, but failed to do so. Thinking he ran Vetrix over, he got off of his bike to look, but it was merely a hologram. He then spotted another hologram of Vetrix and followed it until he was lead into an abandoned warehouse. Vetrix sneaked up behind Shark and put his hands over his eyes; using his crest's power to put him in a trance. Vetrix then put his hand into Shark's head in order to gain control of him for the upcoming Duel with Yuma. He also gave Shark a powerful Trap Card called "Heraldry Catastrophe" to use in the Duel.



Shark turned up for the finals at the Duel Tower for his Duel against Yuma, but, because of Vetrix's powers, Shark was emotionless. This affected his Dueling as Yuma was able to gain a massive advantage over him by his second turn. However, this was short-lived as Vetrix then began to show Shark visions of Yuma and Dr. Faker causing his sister, Rio to be hospitalized. With a dark revenge in his heart, Shark began to relentlessly attack Yuma with his "Spear Shark" and "Two-Head Shark" in combination with "Zeus Breath", dropping Yuma's Life Points in an instant. He then managed to Summon "Number 32: Shark Drake", cornering Yuma further while power of Vetrix's crest glowed on Shark's hand. At the climax of the Duel, Yuma took control of "Shark Drake Veiss", causing Vetrix to lose his hold on Shark. Vetrix was about to establish the same control over Yuma, but Shark came to his senses before it could fully happen. Vetrix appeared before Shark and tried to convince him to save Yuma by using his Set "Heraldry Catastrophe", but Shark refused to submit to Vetrix again, and instead used a "Marine Snow Seal" to banish "Shark Drake Veiss" at the cost of the remainder of his Life Points, resulting in victory for Yuma. Afterwards, Shark thanked Yuma for saving him and encouraged him to vanquish Vetrix. Due to his injuries, Shark is then carried away via helicopter to be treated. During Kite's Duel with Vetrix, the latter revealed that Shark was merely a pawn alongside his progeny and Dextra in order to bolster his "Number 69: Heraldry God - Coat of Arms" with rage and hatred as he had no emotions to spare.



Near the end of Yuma's Duel with Vetrix, Shark awoke, seeing the Sphere Field through the window of the hospital. He watched the remainder of the Duel with Vetrix on television, worrying about Yuma. After it ended, he escaped the hospital and rushed to the stadium, witnessing the explosion of the Duel Tower and the Sphere Field moving towards Heartland Tower. Heading there, Shark encountered Tori, Kite, and Orbital 7. He helped Kite escape from rubble that had fallen on him, and told them his reason for being here. After some arguing, the four agreed to work together and headed to the Sphere Field, but they are stopped by Mr. Heartland, who deployed an army of litterbots to stop them. After Orbital destroys a few, Shark, Kite and Tori wielded fallen litterbot weapons to destroy more of them. When Astral rescued Yuma from the Sphere Field and gave him "Utopia" and "Shark Drake", Yuma returns the latter card to Shark. The three Duelists confronted and challenged Dr. Faker, holding their ace cards high.

As the Duel with Faker began, Shark began to bleed from his stomach from when a litterbot slashed him with it's scythe. He however continued on, managing to Xyz Summon "Shark Drake" as well as protect Yuma's "Utopia" via the Equip Spell Card, "Shield Fin". This strategy enabled the three to inflict 5600 damage to Dr. Faker despite the effects of Faker's "Number 53: Fake-Body God, Heart-eartH". However, Kite mocked Shark for carelessly attacking Dr. Faker without thinking of the consequences, as he received 1400 effect damage from attacking with "Shark Drake". When they thought Kite had defeated Dr. Faker, Shark was shocked to see Dr. Faker had Summoned another "Number" in place of "Heart-eartH".

As the Duel continued, Faker's new "Number", "Number 92: Fake-Body God Dragon, Heart-eartH Dragon" continued to torment the trio, even banishing Yuma's "Number C39: Utopia Ray". When it comes to Shark's turn, Dr. Faker avoids losing via a direct attack from "Shark Drake Veiss" through the "Fake Life". After Shark ends his turn, he falls to the floor in pain as the injury he sustained was worsening. As Kite began his turn, Faker's "Number" banished Shark's "Shark Drake Veiss" and Set card, but while they were being banished, Shark laughed, which shocked Faker. This was because he tricked Faker as his Set card was "Xyz Dimension Splash", which allowed him to Summon two "Ancient Shark Hyper Megalodon" from his Deck. He then allowed Kite to use them as Overlay Units to Xyz Summon "Neo Galaxy-Eyes Photon Dragon" which reduced Dr. Faker down to 150 Life Points. After the attack, Dr. Faker came clean about his actions and why he committed them. After revealing that Vector was the one which ordered him to do such things in order to save Hart, Yuma, Kite and Shark decided to go after Vector. However, at this moment, Vector emerged from a portal and possessed Dr. Faker, continuing the Duel by resurrecting "Heart-eartH Dragon".

When Hart freed Astral, letting him and Yuma merge, Shark's "Shark Drake Veiss" was used to boost Yuma's "Utopia Ray" and help defeat Vector. When Sphere Field Cannon began to explode, Shark pushed Yuma out of the way of a piece of falling rubble, injuring himself further. Orbital 7 was reactivated and got Hart, Shark and Tori out of the place. After Yuma and the others reemerge, Shark is taken to the hospital in a helicopter piloted by Nistro, while Dextra administered first aide. During Kite and Yuma's Duel, Astral mentions that Shark should be able to see Astral due the results of the Duel with Vector. During Yuma and Kite's rematch, Shark was able to leave the hospital (although his chest was heavily bandaged) and witness their Duel. He looked on from a bridge with a smile, muttering "Yuma, Astral" before riding off on his bike.

Yu-Gi-Oh! ZEXAL II
One day after school, Shark went to visit Rio in the hospital, but ran into Yuma on the way, who suggested they Duel. Shark apologizes and declines Yuma because told him he had to go see Rio, then he sensed the arrival of Gilag. Getting an urgent call from the hospital about Rio, Shark rushed there with Yuma and Tori to find Rio crying out in pain. The doctor told Shark that Rio's condition had worsened thirty minutes prior. Rio claimed that disaster was coming and that "they" were coming to take the most important thing, though Shark was confused who are "they". Yuma was called away to save his friends from Fuma, Shark attempted to follow, but Rio clutched his hand and stopped him. Later, Shark eventually left the hospital and intercepted part of Fuma's gang, while Kite intercepted another part of it. The two defeated all of them and then arrived at Heartland Middle School to inform Fuma of his gang's failure and give his support to Yuma to battle against the Barian World.

While leaving school, Shark was approached by Chitaro Ariga, the founder of the Manga Research Club, who wish to used him as model for his manga. He showed Shark his hero character designs that he had based off of Shark, but Shark shrugged him off. When visiting Rio, he gave her one of the rings from their childhood, unknown that Chitaro was spying on him. When Shark heard that Rio's operation was successful, he went to get her when she was discharged, but was met by Chitaro again. Chitaro informed him that he had his sister and that they would have to Duel. Unbeknownst to Shark, Chitaro was working for the Barian World, having become Gilag's most recent pawn. When Shark attempted to counter one of Chitaro's moves with "Zeus' Breath", Chitaro threatened Rio and Shark chose not to activate his card. Wanting to face a "Number", Chitaro gave Shark the components he needed to Summon "Shark Drake", which Shark did. Chitaro countered this by Ranking Up his "Comic Hero, King Arthur" into "Chaos Xyz: Comic Hero, Legend Arthur". As Shark remembered the rings from his sister, the power of their bond shattered the Barian's magic and Rio was freed. The bandages flew off of her face and she insulted Shark's Dueling skills as soon as she opened her eyes, to his irritation. Now able to Duel at his best, Shark defeated Chitaro with "Number C32: Shark Drake Veiss". Shark then reunited with his sister and carried her back to the hospital. Later at school, Shark was shown a samurai-drawing of himself by Chitaro, but he still displayed little interest in it and walked off.

As Rio began to return to school, Shark left their house without her and rushed to school. Despite trying to remain unseen, he met up with Yuma, who asked him what's wrong. Shark began to explain what was wrong, but was interrupted by Rio's arrival, with her calling him mean for leaving without her. Later, Shark ate lunch with Rio, Yuma, and his friends atop of a roof, although Shark sat apart from the group. When Rio started to talk about him, Shark cut her off and yelled at her, but stopped once Rio glared at him. After seeing a group of boys and Bronk smitten with Rio, Shark warned them that Rio is an "ice woman" and they will find out what he means soon. Later, Shark secretly watched Rio Duel against Aika Hanazoe and goes to her after she wins, calling her duel "so-so" and asked if she needs any advice from him. While walking home, Shark talks with Yuma about Rio, and then teased her that she hid behind him when she got frightened by a cat, calling him a "meanie" as a result. When Yuma held a "Sports Duel Tournament" as way for his friends and Rio to stop fighting with each other, Shark was somehow dragged into it as well, and reluctantly participated in it. He was paired up with Yuma, and was able to put their team in the lead with his skills in Dueling and sports. However, Shark leaves to go home before he and Yuma faced Tori and Cathy in the last Duel, leaving Rio and Caswell to explained his unwillingness to in be the tournament any longer.

Manga biography


In the manga, just like as in the anime, Shark is initially a delinquent at school, who has pro-level Dueling skills. However, after Dueling Yuma and being possessed by a "Number", his fate is transformed.

Rio Kastle
Rio is Shark's younger twin sister, whom Shark always tries his hardest to support and protect. He has had a strong bond with Rio ever since they were children, symbolized by matching rings that Rio obtained. Following Rio's Duel with Quattro, in which she was critically injured and wound up in a hospital bed wrapped in bandages, Shark Dueled in the National Duel Circuit for her sake, but the pressure was escalated to such an extent that he peeped at his opponent's Deck before the final match, an action that caused him to be disqualified and banned.

Despite their bond, Shark's brother-sister relationship with Rio seems to be somewhat tenuous, as seen when Rio first presents Shark with the rings as kids, but Shark rejects them, causing Rio to storm off. Also, during Shark's Duel with Chitaro, immediately after Rio's bandages blow free from her eyes and she opens them, she insults Shark's Dueling skills. Shark is seen quarreling with Rio several times, when he's not distancing himself from her out of concern.

Yuma Tsukumo
Shark has been Yuma's friend, rival, and greatest influence ever since their first Duel, in which Yuma was standing up for Bronk. Losing to Yuma causes Shark to become humble, as Shark honors his promise to return Bronk's Deck, and enters a short-lived retirement from Dueling. However, Yuma helped Shark to bounce back, first in a Duel that Shark won without taking any damage, and then in a Tag Duel against Scorch and Chills. From that point on, Shark and Yuma officially become friends.

Shark often warns Yuma not to meddle in his affairs, mostly because they are very dangerous and/or personal, like his vendetta against Quattro. Despite this, Yuma continues to support him throughout his endeavours, including his Duels with Trey, Quattro, and Dr. Faker. He also rescues Shark from Vetrix's influence by taking control of "Number C32: Shark Drake Veiss", to which Shark in turn saves Yuma by banishing it. Shark has also helped Yuma, not only in this way, but also by trying to protect the Emperor's Key when Kite tried to steal it, as well as Dueling alongside both Yuma and Kite against Dr. Faker.

Quattro
Shark's earliest acquaintance with Quattro was at the National Duel Circuit, as he was Shark's opponent in the final match, which he won by disqualification. He becomes Shark's number one enemy when he reveals that he set Shark up for disqualification by placing his Deck so that Shark could see it, and also that he was the one responsible for Rio's injuries. At that moment, he also becomes the reason why Shark enters the World Duel Carnival, spending most of it in Quattro's pursuit. However, Quattro ultimately apologizes for his misdeeds, and entrusts Shark with the task of defeating Vetrix.

Decks
Shark plays a Xyz WATER Deck consisting of monstrous looking sea creatures such as various races of sharks. He utilizes a Burn strategy in order to quickly gain the advantage through cards such as "Submersible Carrier Aero Shark" and "Explosive Urchin", with a focus on using Level 3 monsters, such as "Big Jaws" to Xyz Summon Rank 3 Xyz Monsters.

Shark uses cards that can counter "Numbers", whether that be negating their effects with "Black Ray Lancer" or taking control of them with "Splash Capture". As his Xyz Monsters are Rank 3, their ATK tends to be on the lower side. He includes cards to decrease the ATK of his opponent's monsters such as "Needle Sunfish" and "Friller Rabca" to make up for this. A cautious Duelist, he includes many cards to counter Spells and Traps, such as "Sea King's Verdict", "Mystical Space Typhoon", "Plate Salvage" and "Skull Kraken".

After acquiring "Number C32: Shark Drake Veiss", Shark's Deck shifted to include more Level 4 monsters in order to Summon "Number 32: Shark Drake" and became more focused on the "Shark" archetype.