Reginald plays an Xyz WATER Deck consisting of monstrous looking sea creatures such as various races of sharks and arthropods. His nickname is "Shark" and is derived from his Deck theme and his previous brutal nature. Reginald acquired his Deck from his father at a young age. 
Vector 120 Win (flashback)
In his past life as Nash, ruler of the
United Lands of the Poseidon Ocean, Reginald Dueled Vector in a Shadow Duel using stone tablet cards.
Quattro 12 Lose (Disqualified; flashback)
Pre-World Duel Carnival
Shark utilizes a
Burn strategy in order to gain an early advantage through cards such as " Submersible Carrier Aero Shark" and " Booming Urchin", with a focus on Rank 3 Xyz Monsters. After losing to Yuma he modified his Deck to counter the " Numbers" by negating their effects with his ace monster " Black Ray Lancer" , as well as cards to take  control of them. Reginald's Deck also sports a few cards that destroy Spell and Trap Cards such as " Skull Kraken" and " Mystical Space Typhoon".
World Duel Carnival Preliminaries
WDC Duelist 31 Win
Trey 34 Win
10 WDC Duelists 46 Win (off-screen)
WDC Duelist 46 Win
WDC Duelist 46 Win
Yuma Tsukumo 46 No result
World Duel Carnival preliminaries, Shark continues to use similar strategies as he did previously, with a focus on Rank 3 Xyz Monsters, also adding Level manipulation cards like " Falling Current" and " Hammer Shark". He also utilizes more cards focused on negation such as " Plate Salvage" and " Sea King's Verdict".
World Duel Carnival Finals
After acquiring "
Number 32: Shark Drake", Shark's Deck became more focused around Level 4 Monster Cards and reducing the amount of Overlay Units required for Xyz Summons, such as " Bubble Bringer" and " Xyz Remora". After obtaining " Number C32: Shark Drake Viess" through Chaos Xyz Evolution, Shark also began to use more members of the " Shark" archetype.
Yu-Gi-Oh! ZEXAL II
Deck has become even more flexible in terms of his use of Xyz Summoning, now ranging from Rank 3 to Rank 5. In addition, he also uses a large quantity of cards to swarm monsters to Xyz Summon such as " Tri-Slice", " Panther Shark" and " Eagle Shark". His Deck also features a range of new " Shark" monsters as well as other aquatic fauna like " Big Whale" and " Starfish". Shark also uses a number of cards to reduce the amount of Xyz Material required for his monsters such as " Double Fin Shark", " Xyz Crown" and " Ghost Salvage".
Legendary Number War
Shark's Deck now focuses more on Rank 5 Xyz Summons, primarily his newly acquired "
Numbers" through cards such as " Edict of Atlantis" and " Depth Shark". He also uses a multitude of cards to negate attacks such as " Hide and Shark" and " Deep Current".
Barian Emperor Onslaught
Upon regaining his identity and powers as a
Barian Emperor, Nash continues to use the same Deck he used as a human, with the addition of his new " Over-Hundred Number", " Number 101: Silent Honor ARK", along with its upgraded form. He also supplements his Deck with " Rank-Up-Magic" cards such as " Rank-Up-Magic - The Seventh One", which lets him Rank-Up his "Over-Hundred Number" from the Graveyard, field or Extra Deck and " Rank-Up-Magic Quick Chaos", a Quick-Play Spell Card which allowed him to instantly Rank-Up his " Number 73: Abyss Splash" into " Number C73: Abyss Supra Splash". Nash is also able to perform a " Chaos Draw" which allows him to create and draw cards that allow him to counter his opponent's strategy.
Don Thousand's defeat, Nash acquired the other six "Over-Hundred Numbers" and their "Chaos" versions. He used another variant of this Deck, which focused on swarming the field with those "Numbers", using several support cards such as " Chaos Hundred Universe", " The Greatest Duo of the Seven Emperors" and " Hundred Summon" to Summon them. The final goal of this is to Summon " CXyz Barian Hope", a monster that can use the effects of all the " Chaos Over-Hundred Numbers".
D Team ZEXAL
Sacred Star Knights!!
Ouroboros, Wicked Dragon of Destruction!!
Ouroboros, Wicked Dragon of Destruction!! V1
Ouroboros, Wicked Dragon of Destruction!! V2
V Jump Magazine
Fury of the Waterfall Deity
Numbers Guide 1
Numbers Guide 2
Yu-Gi-Oh! ZEXAL episode 53: " Test Your Luck!"
Yu-Gi-Oh! ZEXAL episode 114: " Tentacles of Terror, Part 1" ↑
; Monster Popularity Poll (place 4) Yu-Gi-Oh! ZEXAL episode 25: " Frozen in Time"