The OC Duelists who will be participating here (subject to additions and subtractions according to the decks I get)

Pat (f.k.a. Patrick Mutou [Pattou]) 
Backstory: The original duelist among the rest. He was once revered but now reviled by others as he was viewed as too laid back or too cautious. Grizzled up internally, he began to speak less and only when necessary and let his dueling do the talking. A self-professed drifter duelist
Deck: Drifter Deck
Ace Card/s: Metalmorph, Wave Motion Cannon, Summoned Skull, The Grand Jupiter, Guardian Angel Joan,  King Beast Barbaros, Guardian Eatos, Phoenix Gearfried, Black Luster Soldier, Freed the Matchless General, Buster Blader
Entrance theme: Broken Dreams by Shaman's Harvest

https://youtu.be/2VP_4DVWUIk

Seph (fka Vaan)
Backstory: Formerly a tactician and strategist. After his loss in the Tag Force Tournament, he has surrendered his old deck and in place, use a new deck that has brought out havoc. He is able to outsmart even the mightiest of foes and sometimes intimidate due to his deck.
Deck: Gateway to the Fall Deck
Ace Card/s: Fallen of Albaz, Albion the Branded Dragon, Sprind the Irondash Dragon, Mirrorjade the Iceblade Dragon, Lubellion the Searing Dragon, Titaniklad the Ash Dragon
Entrance Theme: Gate of Magus from Super Robot Wars

https://youtu.be/SN2Fk9Kv20I

Dino
Backstory: Another duelist with a wealthy upbringing. A braggart in his own right. 
Deck: Dinosaur Deck
Ace Card/s: Ultimate Tyranno, Black Tyranno, SUper Conductor Tyranno
Entrance Theme: For the Love of Money - The O' Jays

https://youtu.be/qxW789jHXII

Tempest
Backstory: Growing up from a rough neighborhood and life, he persevered with his intellect and smarts, which saw him through his dueling. Also a great tactician.
Deck: Winds of Change Deck
Ace Card/s: Simorgh, Bird of Divinity, Storm Shooter, Swift Birdman Joe, Harpy Lady Sisters
Entrance Theme: Just Don't care Anymore - American Fangs

https://youtu.be/vo0_oa1c8vQ

Strike
Backstory: A seasoned warrior turned duelist as seen in his fighting style. He has taken on and adapted to the many types of warriors.
Deck: Band of Warriors Deck
Ace Card/s: Sword Hunter, Great Shogun Shien, Turret Warrior, Gilford the Legend
Entrance Theme: Hellfire -CFO$

https://youtu.be/Idum4bIlGdg

Crow
Backstory: A rebel of the streets, formerly an ally  of Mahad. Grew up in the streets but later on became resilient, as seen in his deck and dueling style.
Deck: Scraps deck
Ace Card/s: Junk Warrior, Scrap Dragon
Entrance: Yusei Fudo's theme

https://youtu.be/0bPEO9_-QSc

Crimson (fka Mahad)
Backstory: Once a protege of Pat, he was gifted with Pat's old ace card, the Dark Magician. He had become too ambitious even to the point he broke away from his mentor and wishes to one day surpass him.
Upon losing to Cobalt, Vade led him to the way to new power and fuel for revenge thru Slifer the Sky Dragon 
Deck: Crimson Retribution Deck
Ace Card/s: Slifer the Sky Dragon
Entrance Theme: Slifer the Sky Dragon Theme

https://youtu.be/QvoFh7lF3SA

Wolfe
Backstory: An avid man of nature, he imbibed nature's ways into his personality and dueling. 
Deck: Bestial Deck
Ace Card/s: Thunder Unicorn, Voltech Bicorn, Lightning Tricorn, Gladiator Beast Heraklinos, Gladiator Beast Gaiodiaz, Gladiator Beast Spartacus
Entrance theme: Wolfpac - WCW (Got lazy, NWO Wolfpac)

https://youtu.be/XQE0oY3sFQ4

Hiro
Backstory: From the rough fusion village to becoming a capable duelist as both a tag team specialist and a singles competitor. One half of the Dual Justice
Deck: Nu Hero Deck
Ace Card/s: Elemental Hero Blade Edge, Elemental Hero Neos, Elemental Hero Great Tornado, Masked Hero Dark Law, Masked Hero Divine Wind, Masked Hero Koga, Contrast Hero Chaos
Entrance theme: Jaden Yuki Theme

https://youtu.be/dc_CYt1uC4g

Kaiser (fka Gizmo)
Backstory: Failed to succeed on his own but a great tag team specialist. Cold and methodical but revitalized with a hunger for victory.
Ace Card/s: Chimeratech Over Dragon,  Cyber Dragon, Cyber End Dragon
Entrance Theme: Giant (a.k.a. Andre the Giant's theme from Smackdown v. Raw 2006)

https://youtu.be/TBqqjk9DxyI

Muto (fka Viper)
Backstory: Formerly of Counter Country, he has felt spurned and feels abandoned and misguided. Upon seeing and obtaining the cards of Yugi Muto, a change happened in him and he begins his rebirth
Deck: Yugi Dark Magician Deck
Ace Card/s: Dark Magician, Dark Magician Girl, Buster Blader, Silent Swordsman LV 7, Summoned Skull
Entrance theme: Dark Magician Theme

https://youtu.be/65Jqq2f4T3I

Cloud
Backstory:  A rather laidback fellow, his facade can be that he is too careless or rather it is a trap to reel in an opponent into an unexpected loss.
DecK: Cloudian Storm deck
Ace Card/s: Cloudian - Eye of the Typhoon, Spiral Dragon, Armityle the Chaos Phantasm
Entrance theme: Wicked Grudge from Yugioh GX OST

https://youtu.be/idFQZcZfvsA

Blaze
Backstory; one of fiery passion that recently joined the fray. A man of ambition but also one of hidden agenda.
Deck: Fenix Deck
Ace Card/s: Manticore of Darkness, Fire King High Avatar Garunix, Sacred Phoenix of Nephthys
Entrance Theme: Slow Chemical - Finger Eleven

https://youtu.be/DMFAzW2SnnA

Vade
Backstory: Lord of Darkness. A man of unknown origin but wielder of untapped power.
Deck: Swift Darkness deck
Ace Card/s: Tragoedia, Rainbow Dark Dragon, Armityle the Chaos Phantasm, Hamon, Lord of Striking Thunder, Raviel, Lord of Phantasms, Uria, Lord of Searing Flames
Entrance theme: Camula's Theme Yu-Gi-Oh GX OST

https://youtu.be/IpJxVx9zDKI

Frost
Backstory: A man of few words but one whose iciness is also reflected in his style of dueling
Deck: Ice Barrier deck
Ace Card/s: Trishula, Zero Dragon of the Ice Barrier, Trishula, Dragon of the Ice Barrier
Entrance theme: Cool as Ice from Super Robot Wars OG

https://youtu.be/57ILmA25gcY

Fenix
Backstory: A warrior now given a chance to prove his worth. A heart strong duelist who strongly believes that he can turn the tides of destiny on his side. One half of Dual Justice
Deck: Heroic Destiny deck
Ace Card/s: Destiny Hero- Dogma, Destiny Hero - Plasma, Destiny Hero - Dystopia, Destiny End Dragoon, XTRA Hero Dread Decimator
Entrance theme: Ash Like Snow - The Brilliant Green

https://youtu.be/l4ZLQJgv-Q8

Irvine
Backstory: One of interesting origin. A rather deceptive individual who can appear innocent yet able to be dispatch any foe quickly. Self professed hacker
Deck: Beginnings of Link deck
Ace Card/s: Encode Talker, Decode Talker
Entrance theme: Judas - Fozzy

https://youtu.be/x2o_wW-llz0

Ryu
Backstory: One of mysterious background. Bombardment expert with untapped potential as a duelist
Deck: Lock and Load deck
Ace Card/s: Quadborrel Dragon, Borreload Furious Dragon, Topologic Zeroboros
Entrance Theme: Drop the Bombshell - Powerman 5000

https://youtu.be/DIZ5FcV64EE

Wallace
Backstory: A man of a dark and shrouded past. Someone who can fight and unleash havoc as both a warrior and duelist
Deck: Phantom Arsenal deck
Ace Card/s: The Panthom Knights of Break Sword, The Phanotm Knights of Rusty Bardiche
Entrance Theme: Annihiliation Battle theme from Samurai Warriors 2

https://youtu.be/ygcqquOadIQ

Odin
Backstory: Self-proclaimed "god" of dueling. A man who can swiftly bring victory at will if able.
Deck: Norse and Worse deck
Ace Card/s: Gullveig of the Nordic Ascendant, Odin, Father of the Aesir, Thor, Lord of the Aesir, Loki, Lord of the Aesir
Entrance Theme: Kotodama Runner from Warriors Orochi 2

https://youtu.be/Ode0oLh7Z2g

Alex Kaiba (AK) (shoutout to @alexrelatado for the OC idea)
Backstory: Alex was adopted by Seto as a young boy, and then took him under his wing and taught him all the ropes of KaibaCorp and Duel Monsters. Alex grew up to be just like Kaiba; ruthless and savage
Deck: Blue Victory Deck
Ace Card/s: Blue Eyes White Dragon, Deep Eyes White Dragon, Alexandrite Dragon, Horus the Black Flame Dragon LV6, Galaxy-Eyes Photon Dragon
Entrance Theme: Seto Kaiba Theme

https://youtu.be/gNrNwrVn0xQ

Cobalt
Backstory: Formerly Xavi. A warrior of proven worth and might. Went through different paths and has wielded various arms to increase proficiency and skill. He has turned to depend on Obelisk the Tormentor as his new source of strength and vessel of power.
Deck: Tormentor Deck
Ace Card/s: Obelisk the Tormentor
Entrance theme: Obelisk the Tormentor theme

https://youtu.be/kMxTT__-wd4

Magnus
Backstory: A spellcaster who wishes to make his mark with his unique style of Spellcasters and Counters
Deck: Endymion Count Magicians Deck
Ace Cards: Day Breaker the Shining Magical Warrior, Endymion, The Mighty Master of Magic, Endymion the Master Magician, Dark Magician, Dark Magician Girl, Magician of Black Chaos
Theme: Vs. the World (Darkside of the City Intro) - Under the Influence (a.k.a. Magnus's TNA Theme)

https://youtu.be/7SA2QXI6ES0

Duke
Backstory: A newcomer from a war torn village that has become a tactician but at the same time, a heavy hitter when it comes to duelling.
Deck: Machina Army deck
Ace Cards: Machina Force, Machina Citadel, Machina Fortress, Ancient Gear Golem
Theme: Special Ops (Intro Cut) - a.k.a. The Shield's Theme

https://youtu.be/r0WtV6nDB80