Here's the Duel that lead to Yuma's darkness and transformation from hero to Barian.

I haven't finshed yet, but was planning for Vector to capture Yuma and bring him back to Barian World, where he places Yuma in a Baria Crystal, erasring Yuma's memories and altering him into a Barian, all the while Vector mocks and taunts the trapped teen.

Note: Vector is in his human form.

And special thanks to Deviantart's OneWingedDaemon for their help.

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Starting Scores:

Vector: 4000

Yuma: 4000

"Third time's the charm. So I think I'll go first." Vector said, before he drew the top Card from his Deck and made his move.

"I Summon Umbral Horror Unform in Attack Mode!" (0/0) Vector announced as he placed the aforementioned Monster Card on his Duel Disc, causing shadows to form before Vector until they transformed into the fiendish Monster Vector had called upon.

"And with that I'll end my turn." Vector then said simply, confusing Yuma and Astral.

'He played a Monster with no Attack or Defence Points and no Set Cards?' Astral commented to himself in confusion, which caused Yuma to question out loud demandingly. "What are you up to, Vector?"

"The both of you will see very soon. But I should warn you, you shouldn't be worried about the Cards on my Field but the Cards I have in my hand." Vector told Yuma and Astral in a wicked reply.

"The same goes for you too. I draw!" Yuma yelled out as he drew the sixth Card from the top of his Deck and began his turn.

"I Summon Goblinbergh!" (1400/0) Yuma announced, before the Winner of the World Duel Carnival explained. "And thanks to his special ability, Goblinbergh can transport another Monster from my hand straight to the Field, so long as it has 4 Stars or less. And I choose Kagetokage!" (1100/1500)

It was then the trio of bi-plane flying goblins dropped a large steel container, which opened up, revealing the shadow-shifting lizard.

Now that the stage was set Yuma exclaimed. "And now it's Overlay time! With these two Monsters I build the Overlay network. I Xyz Summon Number 39: Utopia!" (2500/2000)

It was then Kagetokage was engulfed in a dark purple light, while Goblinbergh was engulfed in a bright yellow light, before the pair shot off into the air, twisting around each other, as a portal opened up in front of Yuma, before both lights then shot into the portal, creating a massive explosion of energy as Yuma's signature Monster appeared on the Field.

"Impressive. But it's going to take more than that to stop me!" Vector told Yuma in a wicked tone.

"We'll see about that. But for now I'll just Destroy your Monster!" Yuma snapped back, before the black and red spiked haired teen commanded in a determined tone. "Go, Utopia and Attack Umbral Horror Unform with Rising Sun Slash!"

Doing as Yuma had commanded, Utopia drew the blade from his right sheath and sliced Umbral Horror Unform in half, throwing Vector back from the blast and knocking him to the ground as he was struck with 2500 Points of Damage.

"What do you think of that, Vector?" Yuma asked mockingly, however, he and Astral were confused yet again as Vector got to his feet and began to let out another wicked laugh.

"What's so funny?" Yuma questioned.

"What's funny is how foolish you are. Thank you, Yuma for your assistance. You've fallen right into my trap!" Vector replied, which caused Yuma to question further. "What are you talking about?"

"When Umbral Horror Unform is Destroyed, I'm allowed to Summon two Umbral Horror Unform copies from my Deck in its place. So thanks a lot, Yuma." Vector explained as the shadows that were once Umbral Horror Unform began to mould and reshape until there were two Umbral Horror Monsters on Vector's side of the Field.

Seeing that he had been tricked yet again by Vector and his deceptive ways caused Yuma to let out a small groan of frustration as the Number Hunter could tell that Vector would try to Xyz Summon Number 104: Masquerade (2700/1200) and possibly Masquerade's Chaos form next turn, in which Yuma then said. "I play one Card face-down and end my turn."

Current Scores:

Vector: 1500

Yuma: 4000

"I activate Monster Reborn. So now my third Umbral Horror Unform will be welcomed back from the Graveyard with open arms!" Vector announced as the magic of Monster Reborn caused Vector's first Umbral Horror Unform to arise from the Graveyard and appear in the centre of the other two Umbral Horror Monsters.

"This is not good." Astral stated in a worried tone.

"You've got that right, Astral. Because I now Overlay all three of my Umbral Horror Unforms! With these three Monsters I build the Overlay Network! I Xyz Summon Number 104: Masquerade!" Vector exclaimed in a mixture of fury and insanity as all three of Vector's Umbral Horror Monsters were engulfed in lights of dark purple, before the darkness shot off into the air, twisting around one another, as another portal opened up, only this time in front of Vector, before the forms of dark energy then shot into the portal, creating a massive explosion of energy as Number 104: Masquerade appeared before his Summoner.

"Now, feel my wrath, Yuma!" Vector exclaimed wickedly, before he commanded. "Masquerade, Attack and Destroy Utopia!"

Quick to act and save Utopia, Yuma announced. "Not so fast, Vector! I activate the Xyz Weight Trap Card! Now Masquerade loses 800 Attack Points for everyone of its Overlay units!"

It was then Masquerade's Overlay units transformed into chains and Vector's Monster's Attack power was greatly reduced. (2700→300)

However, Vector suddenly called out. "Fool! I activate the Spell Card: Trap Booster! By discarding one Card from my hand I can activate any Trap Card from my hand!"

"What!?" Yuma questioned in shock and disbelief.

"I told you to beware the Cards in my hand because I now activate my Trap Card: Nightmare Chains!" Vector exclaimed manically as he placed the Trap Card in his Duel Disc, causing the chains around Masquerade to break apart, only to then ensnare around Utopia as a stone slab arose behind Yuma's ace Monster, binding him to the wall.

"Utopia!" Yuma called out in concern for his Monster, before the black and red spiked haired teen yelled out. "What have you done!?"

"Simple. With the power of my Nightmare Chains I was able to rid my Monster of your pitiful Trap Card, and there's more. I can select any Monster on the Field and trap it. Preventing Utopia from Attacking me or protecting you!" Vector explained, amused by his antics and the predicament of torment Yuma was in, before he then commanded. "Now, let's try that a second time. Masquerade, Attack again, only this time your target is Yuma directly!"

With the Nightmare Chains keeping Utopia restrained, Yuma was unable to defend himself against Masquerade, in which Masquerade threw one of the gold rings at Yuma, which grinded painfully against the Number Hunter's chest, before he cried out in pain as he fell to the floor.

"A good time to end my turn, but not before one last surprise." Vector announced in wicked amusement, before he placed a Spell Card within the first slot of his Spell/Trap Card zone on his Duel Disc and then went on by saying. "I activate my Exchange Spell. Now each of us select a Card in our opponent's hand and select one to use."

Having no choice, Yuma turned his Cards around for Vector to see, revealing he was holding a Spell Card and two Monsters, Double Bind, Rai Rider (1200/1400) and Traplin. (300/400)

It was then Vector tossed the only Card within his hand to Yuma, a dark red aura radiating around the Card as he caught it.

But before Yuma could see what Card he was given, a dark claw shot out from Vector's Duel Disc, took Yuma's Traplin Card and added it to Vector's hand, ceasing their opportunity to free Utopia from Vector's Trap Card.

Current Scores:

Vector: 1500

Yuma: 1300

"My turn. I draw!" Yuma announced strongly as he drew the top Card from his Deck, hoping for a game changer, in which the Number Hunter looked to see he had drawn Kurivolt (300/200), causing him to state. "Alright, not the best Card. But it can help."

"I play..." Yuma began to say, however, Vector suddenly interrupted, shouting out Yuma's name, causing the Winner of the World Duel Carnival to stumble for a moment.

"Aren't you forgetting something?" Vector asked.

Yuma was confused as to what Vector was talking about, until Vector then said. "The Card I gave you."

"What Card?" Yuma asked, before it was then he remembered that Kurivolt wasn't the only new Card added to his hand, in which the red spiked haired teen looked to the other Cards in his hand, causing his eyes to widen in shock at the dangerous Card he was now wielding, Rank-Up-Magic Barian's Force.

Seeing Yuma now possessed such an evil Card shocked Astral and caused him to question. "Vector, what is the meaning of this?"

"I just want to give little old Yuma a fighting chance, that's all." Vector replied in a wicked tone, before laughing in amusement, which caused Astral to then ask in confusion. "A fighting chance?"

"That's right, if you don't believe me, just look at the Field!" Vector pointed out, before he explained. "Utopia's all chained up and unable to protect either of you while Masquerade is free to strike at Yuma's Life Points and finish you both off for good! And no Card in Yuma's hand can help, meaning you've only got one option if you want to win... And we both know what that means, don't we?"

"Stop this, Vector! The Yuma I know would never play a card like Rank-Up-Magic Barian's Force!" Astral stated, but it was then Vector replied mockingly, referring to Rank-Up-Magic Limited Barian's Force. "Oh, but he did, didn't he?"

Vector then asked curiously. "Although that Card was just a portion of the power of Barian, it was still a Barian Card. So how do you know he won't play the REAL Barian's Force?"

It was then Vector turned his attention back to Yuma, whose gaze was transfixed on the Card, and asked him. "And Yuma. What'll happen to your little friends if you lose? Have you ever thought about that problem? Or are they all just a secondary thought to you?"

Hearing that filled Yuma with anger and caused him to yell at Vector threateningly. "If you dare lay a hand on any of them, I'm gonna..."

However, Yuma was interrupted when Vector suddenly called out. "You're gonna what? C'mon, Yuma, tell me what will you do? Let's face it; you're in a very tight situation right now."

"Poor Yuma Tsukumo, look at yourself, you're powerless. Utopia is helpless against Masquerade, plus, I got a good look at your hand and none of those Cards of yours can save you." Vector explained, before he said. "So, even if you Summon one of those pathetic little Monsters in a desperate attempt to protect yourself, there's no way you can stop Masquerade without Ranking-Up Utopia. Or maybe you like to idea of him being chained and useless?"

'He... He's right. Rai Rider and Kurivolt won't be able to stop his monster. And even if Utopia wasn't caught in Vector's Nightmare Chains I can't use Double Bind since Utopia's Attack hasn't dropped...' Yuma thought to himself as he stared blankly at Vector's Card, while doubt plagued and clouded his mind, causing a distant look to fill his eyes. 'If I use Barian's Force, I have the chance to save everyone, but who knows what'll happen to me... Or Astral...'

"Well, Yuma, I'm waiting. What're you going to do? Have me finish you off and move onto destroying all your friends and your world? Or use my gift and at least stand some chance of winning?" Vector questioned mockingly, before he further mocked Yuma and stated. "Either way, I'm having a blast."

"Yuma, do not listen to him! We do not need to use that Card, there is always another way!" Astral told Yuma, hoping to get through to his friend.

However, it seemed as though Astral's words were in vain when Yuma replied in a distant tone, as the combination of Barian's Force, Astral's life and the safety of his friends was taking its toll on the Number Hunter, further amusing Vector. "But Astral... What about you...? If we lose, you'll disappear forever... The Barians will get our Numbers and will destroy Astral World... And if I make any other move, I know Vector will counter it and everyone will be in danger..."

It was then Yuma slowly withdrew Rank-Up-Magic Barian's Force from his hand, his eyes went dull as he stared blankly at the Card. "Rank-Up-Magic Barian's Force is our only hope..."

"Yuma, no!" Astral called out in concern, before Vector yelled out in amusement. "Yes, Yuma, yes!"

"None of your other monsters will be able to stop me or my Masquerade." Vector stated arrogantly, before he explained. "And even if you do hold on, Masquerade can get rid of the top Card from your Deck every single turn, meaning you'll be with less Cards whenever you draw and will soon be out of Deck!"

"No matter what alternative plan you try to make, your end is inevitable!" Vector stated manically, before laughing cruelly, in which Astral could see Vector's manipulative words were getting to Yuma's head, causing him to plead. "Yuma, I am begging you, please, do not use that Card!"

However, it was to Astral's shock that after Yuma's eyes returned to normal a Barian emblem then appeared on Yuma's forehead, before the Winner of the World Duel Carnival exclaimed. "I... I'm sorry, Astral... But I need to stop Vector... No matter what...!"

"I activate Rank-Up-Magic Barian's Force!" Yuma exclaimed as he held the Barian Card upward, causing an aura of Barian energy to radiate from the Card, shocking his friends, before it was then Yuma was encircled in the same aura of energy, causing him to cry out as the power of Barian surged through his body and forced Astral to let out cries of pain, before he was forced back inside Yuma's key.

But with the last trace of good within him, Yuma tore the key from around his neck and threw it away, saving Astral, before he announced, as he was consumed by the power of Barian's Force. "It's over, Vector! I rebuild the Overlay network with Utopia! Go Chaos Xyz Evolution!"

With the power of Rank-Up-Magic Barian's Force, Utopia broke free form Vector's chains, before Yuma's ace Monster transformed into a form of dark red energy, which shot into the sky and into a vortex, creating a massive explosion of Barian energy.

"Barian's power, formed by chaos, use your power to evolve Utopia from a form of light to that of chaos! Come forth Chaos Number 39: Utopia Ray V!" (2600/2000) Yuma announced in a darker tone, never heard from him in the past, before, standing in Utopia's place was his Barian counterpart, Utopia Ray V, his Overlay units had transformed into Chaos Overlay units, causing Vector to think to himself in an amused and wicked tone. 'I see you made the smart choice of playing my Card. But it will only be the end of you. Poor Yuma, you are so predictably pathetic. Place anyone of your friends in danger and you can pull his strings like the puppet he is.'

"I now activate the power of Barian's Force!" Yuma exclaimed, before he told Vector darkly. "Now Masquerade's Overlay units are taken away and added to mine! Go, Chaos Drain!"

It was then Masquerade's three Overlay units were forcefully pulled over to Yuma's side of the Field and transformed into Chaos Overlay Units, before Yuma yelled out in a dark tone. "Now your Monster loses 300 Attack Points for each Overlay unit I stole!" (2700→1800)

But the decrease in Masquerade's Attack power didn't matter to Yuma; all that mattered to him now was revenge, in which the Number Hunter yelled out in fury. "And now for some serious Damage. I activate Utopia Ray V's special ability! By using a Chaos Overlay unit I Destroy Masquerade and you take Damage equal to that Monster's Attack Points!"

"Go, Utopia Ray V, take down Masquerade with Spinning Blades of Destruction!" Yuma commanded, in which Utopia Ray V withdrew his blades, combined them into a single weapon and threw the Barian weapon directly at Masquerade, causing Vector to get slammed with 1800 Points of Damage as his Monster was Destroyed in a massive explosion, knocking Vector to the ground, the Duel was over, or so it seemed.

"I'm not finished, Vector!" Yuma yelled out, as Vector rose to his feet, before the red spiked haired teen exclaimed in a tone of mindless vengeance. "Utopia Ray V, I command you to Attack Vector directly! Destroy him, make him pay for everything he's done!"

Doing as commanded, Utopia Ray V shot forward and struck into Vector's chest with his blades, causing Vector to let out a mixture of pain and laughter as he was launched back from the devastating power of Yuma's Attack and slammed to the ground.

Ending Scores:

Vector: 0

Yuma: 1300

As the Duel ended, Yuma could feel that the power of Barian's Force had drained him of almost all his energy, in which the red spiked haired teen slowly collapsed.

"I'm sorry..." Yuma managed to let out in a weak tone, before he fell into unconsciousness and slowly to the floor.

However, before any of Yuma's friends could react to assist their fallen friend, Vector held out his hand, which began to glow a shade of heliotrope and surrounded Yuma in a light aura, pulling his unconscious form over to him.

"Yuma!" Tori yelled out in a concerned tone.

"I might've lost the Duel but I still get a prize!" Vector replied, referring to his captive as he held the unconscious Yuma by the back of his jacket up to his friends.

(More later.)