I don't own Yu-Gi-Oh! 5D's. As stated in the summary, this is an AU of the Dark Signers arc.

Chapter One- Light or Shadows

Yusei's eyes widened with fear as the Earthbound Immortal's hand came closer. He had no way to avoid it. He had no cards on the field and his monsters wouldn't be able to help as the Immortal could bypass them and attack directly. He heard his friends cry out his name and he closed his eyes as the hand came down and his life points went to zero. He waited to feel himself being swallowed by the shadows and sent to the Netherworld; in fact he waited to the point that he slipped off his rider and passed out.

Kalin watched in delight as his monster ended the duel and Yusei slipped off his rider. I did it! I got my revenge and Yusei's going to the Netherworld! Kalin cackled in triumph, his eyes fixed on his old friend to see him disappear. Instead a purple light surrounded him and his rider, lifted both into the sky, and streaked off into the distance. Kalin blinked in surprise. He should have gone to the Netherworld; instead he seems to be headed for our headquarters.

"Hey, where'd Yusei go?" Crow demanded, snapping Kalin's attention to him.

Kalin smirked as he suddenly had an inkling of what Roman had in mind. "Oh, don't worry about him. Once my leader's interrogated him, he'll send Yusei to the Netherworld!" He revved his Runner and took off, cackling.

Crow exchanged worried looks with the twins before looking up at Jack. What was going to happen to Yusei and their fight against the Dark Signers?

Yusei awoke suddenly to a burning sensation on his arm. He sat straight up and gripped his arm. His mark. It was glowing and burning. A Dark Signer must be nearby; that would explain the burning feeling, he thought, staring at his mark. He then realized that he was on a bed and alone. He hopped off the bed and headed for the door with the intention of leaving. He grasped the knob and tried to turn it: Locked.

"Hey! Let me out!" he demanded, pounding on the door. He pressed an ear to the door to hear nothing. He knew he was a prisoner of the Dark Signers, but didn't know exactly why, though he did have one idea: He was bait for the other Signers. He sat back on the bed and studied the door, but soon gave up. The hinges were on the other side and there was no keyhole to pick the lock. He was effectively trapped and could only wait for someone to come for him. He groaned and put a hand on his glowing, burning mark.

"When will you interrogate him?" Kalin asked eagerly.

Roman didn't reply immediately; he was running his fingers lightly over his glowing mark. "I do not intend to interrogate him. I intend to persuade him to join us."

"Yusei? A Dark Signer?" Devack inquired. "You think he will join us?"

Roman smiled. "Oh with some bending of the truth and perhaps if I bond with him using my mark." He put a hand on his arm. Yes, he thought. If I share my mark with Yusei, it will take control of him the way it did me, for I was a Signer before I chose the path of darkness. Roman stood. "Devack, head to New Domino City to pick up our comrade and maybe recruit two more people as Dark Signers."

Devack nodded and left to head for the city while Roman headed for the room Yusei was in. He unlocked the door and slipped inside, closing it and leaning against it as he faced Yusei who had gotten up and faced the door.

Yusei got up from the bed and faced the door as it opened slightly, allowing Roman to slip in and close the door. He smiled down at the young man, his eyes glancing at Yusei's arm for a moment. "Hello, Yusei. I am Roman, leader of the Dark Signers."

"What do you want with me?" Yusei snapped. "Are you using me as bait?"

"Bait?" Roman laughed. "No, not at all. I want to talk to you that is all."

"I have nothing to say to you."

Roman was silent for a moment. "You fear me or at least the Earthbound Immortals."

Yusei wanted to deny both claims, but his loss to Kalin still rattled him. The image of Ccapac Apu's hand coming at him flashed through his mind. He turned away from Roman, determined not to let him see the fear in his eyes.

Roman grinned as Yusei turned away. Oh, yes. The Immortals scare him. I can use that to my advantage. "You do fear the Immortals. You'd rather not face them again. All you have to do in order to do that is walk away from all of this."

"That would be the easy thing to do, but I can't." Yusei faced Roman. "I have to stop you and the other Dark Signers."

"Why? Because Goodwin said so?"

"Yes."

Roman shook his head. "Have you forgotten what Goodwin did to get you to duel in the Fortune Cup? He captured your friends. He manipulated you to seek out the Dark Signers. You can't trust him." Roman reached out with his right hand and grasped Yusei's left arm. "My friends and I are not the enemy. Goodwin is the one who needs to be destroyed, to pay for what he did to you. I can help you to get back at him." Roman's mark glowed brightly and Yusei cried out in pain. His left arm was burning. Roman released him and Yusei grasped his arm. He looked at it and gasped. There, visible through his glove, was a purple spider mark on his arm that was glowing! "Why is there a purple mark on my arm that's just like yours?"

"I am sharing my mark with you. You see, I am the fifth Signer. I had the mark of the dragon and the mark of the shadows. You and I are now alike. We both have two marks. However, I have chosen the shadows and distanced myself from my dragon mark." Roman removed his left glove to reveal a metal hand and arm! He replaced it and headed for the door. "I will leave you to consider your options." He opened the door, left, and locked it.

Yusei removed his gloves and pushed back his jacket sleeves to examine the marks. Both weren't glowing now, but still visible, which made sense. He looked at the left; he hated bugs and he now had a spider mark- a mark of the shadows as Roman put it. He claims we're the same, but he's wrong. I will not choose the path of darkness. Maybe my dragon mark can cancel out and destroy the other. Yusei placed his mark on top of the spider.

Red and purple energy crackled around the room and Yusei cried out before separating the marks. The energy ceased and Yusei winced slightly. Okay, bad idea. But, I will fight back anyway. He laid back on the bed, closed his eyes, and drifted off to sleep, believing he would have more energy to fight back and defeat the dark mark.

Roman sat alone at the table, Kalin having gone to spy on the Signers to see what they were doing. They are most likely working on a rescue plan, Roman thought. Well, we can't have that. Yusei will be a Dark Signer. Our bonded Mark will influence his thoughts as he thinks on what I said and it will influence him more quickly if he sleeps. I know there's fear in his heart and I hope anger takes root as well.

Yusei awoke again to a burning sensation. He sat up and saw both marks were glowing. He sensed a connection through the dragon one. A Signer was dueling a Dark Signer…and it was in the city! Whoever it is, I hope they don't meet an Immortal. He shuddered as his last duel went through his mind again. He pushed it asked and he dwelled on Roman's words. He chose to be a Dark Signer. I will not do that.

He knew how I ended up in the Fortune Cup, what Good win did. Yes, he did hold my friends captive to gain my cooperation, but he knew what was to come. I don't trust Goodwin, but he had the information the Signers needed. Yusei saw the marks stop glowing. The duel was over, but who won? I hope our side did or that the duel was interrupted.

Our side. Which side am I on? I have two marks. I can't be on both sides as they're in opposition to each other. He put a hand on the dragon mark. I've had this one since I was born and it only recently became visible. The other one was forced on me. My birth mark is a sign of light and hope while the other is darkness and shadows. It is clear which one is desirable. Yes, it's…

The spider mark glowed softly and Yusei's blue eyes darkened slightly and his brow furrowed. Or is it clear? After all, how can I believe Goodwin will keep his word to complete the bridge? He's manipulated and threatened me in the recent past. He manipulated others to achieve his own ends. Anger at Goodwin filled his heart and mind alongside his fear. He wanted Goodwin to pay for his deeds and the shadows would give him the power to do so. He just had to turn his back on the Crimson Dragon and accept the King of the Netherworld. An image of the world under the control of the king and the Dark Signers appeared in his mind and he found that he actually liked it. The spider glowed brighter as it fed on his anger and fear. A cruel smile came to Yusei's face, his two marks switched places so that the spider was on the right and the dragon on the left before the latter vanished. A pillar of dark energy erupted around Yusei and when it ceased, he was dressed similar to Roman, his Facility mark had turned red, and when he opened his eyes, the whites were black. Yusei laughed softly in a dark tone. He was now a Dark Signer.