AppearanceEditShark 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. He also owns a grey and green Duel Gazer with a red lens and a yellow spike. He also wears a large red jeweled, yellow pendant that resembles a Barian Emblem. His attire includes a dark purple jacket over a black shirt and dark pants with white, green-gems shoes. When in his school attire, he wears a white shirt with green-lined sleeves, tie and a collar.
Ryoga has been shown to be extremely cruel, shown when he snatched Tetsuo's Deck and then snapped Yuma's pendant just to show Yuma that he was powerless. Despite this, he is shown to keep his word as he gave Yuma Bronk's Deck after he was defeated.
HistoryEditShark is an orphan, and was raised in an institute, together with Kyoji Yagumo. He and Kyoji were like light and shadow there, but they weren't on bad terms.
Yu-Gi-Oh! ZEXALEditOne day after school, Shark had a Duel with Tetsuo Takeda, which was watched by Yuma Tsukumo and Kotori Mizuki. When Shark defeated Tetsuo, he took his Deck. Tetsuo revealed that Shark and his friends had taunted Tetsuo to the extent that he bet his Deck on the Duel. Yuma attempted to defend Tetsuo, but Shark took Yuma's pendant and snapped it. He then told Yuma to challenge him to a Duel in front of the Heartland train station in order to win Tetsuo's Deck back, but he must put his Deck on the line. Shark overpowered Yuma during the Duel, but when Yuma decided to believe in himself, his broken pendant restored itself, and Yuma uses it to open the door of his dreams. When he does so, a dark card, called a "Number", possessed Shark, making him even stronger. However, at the same time, a mysterious entity, called Astral appeared before Yuma, and told him to "stand up and win". Astral then helped Yuma during the Duel, but they find out a "Number" can only be destroyed by another "Number", and when two of them battle, they do to consume each other. Astral gave Yuma a "Number" as well, and they managed to defeat Shark. As Shark gave Tetsuo's Deck back, Yuma said that the Duel was fun, and that they should Duel again. Shark said that he won't forget that, and leaves. Shark later appeared after Yuma was almost defeated by Kaito Tenjo, looking annoyed at how Yuma was behaving because of his defeat.
She soon revealed herself as Luna, and said that Shark can call her an emissary from the moon. Shark replied that she looks like something straight out of a fairy-tale, not that he hates them. Luna replied that she doesn't have any ill will against him, but she must face him. They then began a Duel.The Duels ended quickly, with Shark defeating Luna in an OTK. After he won, Shark asked Luna if she is alright; she is impressed that Shark could Summon three Xyz Monsters at once during the Duel, and said that she wasn't wrong. Luna revealed she is a Numbers Hunter whose goal is to eliminate the "Numbers", and says that Shark is the only one who can stop Dr. Faker, and for that he needs the power to do so - a "Number". Shark declined, saying that he was already once possessed by a "Number", and that he cannot do so. However, Luna replied that he knows how terrifying a "Number" can be, and that this is just why it would be okay. She further explained that "Numbers" are mirrors that reflect the hearts of the people, and at that time, his heart was full of darkness, but Yuma and Astral freed him from that darkness. She then gave Shark a mysterious card, and said that it's a new power that will protect him
Later, Shark Duels a self-made store owner, whose business was going well because of the power of a "Number" card. Shark won easily using the new "Number" Luna gave him, "Number 47: Nightmare Shark", and obtained the store owner's "Number 63: Shamoji Soldier". Then, Yuma and Astral appear, and meet him. Before they could say anything, Kaito Tenjo appeared as well. Shark recognized Kaito, and Kaito says that as Shark knows his name, he seems to have became rather famous. Luna then appeared, and told Kaito that's because she told Shark the truth. Later, when Kaito tried to use his Photon Hand on Luna, she put her hand over the amulet on her chest, which created a kind of barrier covering her, Shark, Yuma and Astral, and reflecting the Photon Hand. The four are then instantly transported to the outskirts of Heartland City. Yuma and Shark stared at each other for a moment, and Shark told him that he would wipe out his "Numbers" as well one day, as he turned to leave with Luna. 
Yu-Gi-Oh! D Team ZEXALEdit
Tokunosuke wanted to enter Shark's Dueling Team, but he said he'd only accept Tokunosuke if he defeated the leader of Team ZEXAL, Yuma Tsukumo. However, Tokunosuke failed to do so, and rushes up, but he is despised by Shark's Team.
Shark called Team ZEXAL weak, and challenged Yuma to a Duel under some conditions: first, they will bet their teams' badges, which symbolizes the pride of the team; and second, if Yuma lose, Tokunosuke will enter Shark's team as a slave who does every work. With no other option, Yuma accepted the Duel.
Astral instructed Yuma on how to Duel, but Yuma didn't listen to him, which led to his loss. However, when Shark attempted to take his badge, he sees Yuma's cards, and noted that Yuma could have won. Because of that, he declared the dispute as invalid, and told Yuma that the next time they Duel, he'd use his true strength.
- ↑ 1.0 1.1 1.2 Yu-Gi-Oh! ZEXAL Rank 1: "The Name's Yuma!!"
- ↑ 2.0 2.1 Yu-Gi-Oh! ZEXAL Rank 4: "The Light of Hope!!"
- ↑ Yu-Gi-Oh! ZEXAL Rank 21: "Kyoji Yagumo!!"
- ↑ Yu-Gi-Oh! ZEXAL Rank 2: "A Mysterious Life-Form?!"
- ↑ Yu-Gi-Oh! ZEXAL Rank 3: "Astral!!"
- ↑ Yu-Gi-Oh! ZEXAL Rank 10: "New Enemies!!"
- ↑ Yu-Gi-Oh! ZEXAL Rank 18: "Kaito, Again!!"
- ↑ Yu-Gi-Oh! ZEXAL Rank 19: "Messenger from the Moon!!"
- ↑ Yu-Gi-Oh! ZEXAL Rank 20: "A Three-Way Battle!!"
- ↑ Saikyō Jump
- ↑ Yu-Gi-Oh! D Team ZEXAL Chapter 2: "An Instant Turnaround by Magic!!"
- ↑ Yu-Gi-Oh! D Team ZEXAL Chapter 3: "The Trap of the Counterattack!!"
- ↑ Yu-Gi-Oh! D Team ZEXAL Chapter 4: "Conclusion of the Fierce Fight!!"