Upon revealing the truth to her friends, Yukina and them set themselves to find Diego. Diego is the head of an organization called the Black Ace organization. Inside that organization, they hold a dangerous card called Malicious Fiend: Life Destroyer. According to Yukina, if the card is ever released, it will bring much destruction. Hoping to get the card before that happens, Yukina and her friends managed to find Diego's base and went on inside. They are aware they could be walking into a trap, but this is of great importance to Yukina.

"Well, we're inside. Now what?" Cindy questioned. They looked around and saw there was no one around.

"Where are you, Diego?!" Yukina called.

"Do you mean little old me?" Diego said as they could hear his voice. "I'm so glad you could make it, my friends. It's nice to see all my efforts weren't for nothing."

"Where are you? Show your face so I can clobber you for making a fool of me!" Cray demanded.

"I wasn't making a fool of you. I just simply wanted to gather data on Yukina to see how strong she was." Diego said. "The data I gathered on the duels you've all been in has been quite helpful."

"On all of us?" Felix questioned.

"I get it now! That's why he gave me my Heatsoul deck! He was using all of us from the very start!" Kent said. "He must have been spying on us since Yukina came to town!"

"Where are you?! Get out here!" Yukina called.

"Very well. I'm at the top floor in the dining hall. Come and make your way up...if you can." Diego dared.

"The top floor... If he's revealing his location, he must be pretty confident." Cray said.

"That's fine with me. I'm not going to back down to the likes of him." Yukina said.

"I'm with you, Yukina." Cindy said.

"Let's go, but we need to be careful. If he has data on all of us, he must have set some measures to counter our decks and such." Felix advised. All of them moved deeper into the base to try and get where Diego says he is. The first thing they found was the elevator, but nothing happened when they tried using it.

"Figures the elevator would be out." Yukina said.

"We be sitting ducks in there anyway." Felix said. "Cray, you've been here. Do you know the layout?"

"It's not like I was taking a tour around here." Cray said. "Although, I do know where the training area is. It's not that far from here. I believe there was a set of stairs near that area."

"Let's check it out!" Cindy said as the four of them got moving to the training area Cray spoke of. Of course, Diego wasn't going to make it easy for them.

"You didn't think it would be that easy, did you?" Diego taunted.

"I just met this guy and I already hate the sound of his voice." Felix said as they all could just tell he's got something for them.

"Let's have a ball...or should I say top." Diego said. That was when the ceiling up ahead opened up and a giant top came straight down and was heading straight for them.

"What the heck?!" Kent called.

"I thought they studied duels! Not make giant tops!" Yukina said. All of them turned right around and went back, but that was right when a door came down and trapped them.

"Now what?! What do we do?!" Cindy said. It didn't look good for them. As Yukina looked back, there was only one way around it.

"We've got no choice! We have to jump through the opening in the side!" Yukina said as she and Cray went for it.

"Hold on a minute!" Kent called, but the two of them already dived right through and got around it. Felix and Cindy followed their lead and jumped right through. "Problem! I won't be able to fit through there!" It didn't look good for Kent as he was too big to fit through.

"Come on, Kent!" Yukina called.

"But how is he going to get around?!" Felix said. Kent was trapped. With no time to think, Kent actually tried to jump right over it. With some great physical strength, he actually jumped right over the top and made it.

"Hoo! That was close!" Kent said.

"Yeah, but maybe it's time to lay off the burgers." Yukina said.

"Hey!" Kent complained as he felt insulted.

"Let's move!" Cray said as the five of them got moving again. The five of them kept moving until they came across the next room and found themselves in the training area that Cray mentioned. "This is it. This is where Diego kept me and other duelists."

"Look at all that equipment." Felix said as they noticed all the fancy equipment in the room.

"All of it used to measure a duelist's physical capabilities, help improve, and helps them become better duelists." Cray said. "Having a body that can endure is good for a duelist, and it can also help sharpen the mind."

"Look! The other side is opened up!" Kent said as he pointed to the other side and showed a clear opening to the next hall. "Let's move it!"

"Wait!" Felix said as he prevented Kent from doing anything.

"Something seems off. It's too easy." Cindy said.

"This would be an ideal spot for a trap." Felix said as they all had a bad feeling about this.

"Or perhaps an ambush!" Diego called. That was when a series of secret passages opened up and some other duelists that worked for Diego came out of hiding and was facing all of them. They all looked like they wanted a duel as they activated their duel disks and each one fo them was summoning a monster.

"I didn't know Diego had so many duelists under his thumb!" Yukina said as they didn't like the looks of this.

"What do we do?!" Cindy said as they were all outnumbered.

"We fight! What else?!" Kent said as he was ready to rumble.

"Guys, the door!" Felix said as they saw it was closing. "Forget them! Go for the hall!" All of them tried to get their way around the monsters and the duelists so they can get around. Yukina and Cray were able to move around their enemies and slid under the door.

"Guys!" Yukina called as they weren't so lucky to get around as the enemy monsters prevented them from going anywhere.

"We'll be fine! You guys just go on ahead! We'll catch up with you!" Felix called just before the door closed on them.

"Felix! Cindy! Kent!" Yukina called as she banged on the door, but it wouldn't move or go up. "There's got to be a way to get this door open."

"There's no time. We'll just have to go on without them." Cray said. "They'll probably find their way. Aren't you all about friendship and such? Isn't part of that believing in them?" Yukina didn't want to leave them behind, but Cray is right. They needed to focus on what they were here for.

"Yeah... Let's keep going." Yukina said as the two of them went on without their friends and headed up the stairs.

...

Diego

Diego helped himself to some dinner while also monitoring the actions of Yukina and her friends. He watched as the others dueled his underlings and saw they were doing rather well.

"It seems that they're not completely useless after all." Diego said. "They certainly have great physical traits as well dueling skills. I wonder how they will do when he wakes up." It seems that Diego is buying time for something, but who could he be talking about?

...

Yukina and Cray

"Why couldn't he have kept himself on the second floor?" Yukina complained as the two of them made their way up the stairs. She and Cray kept going until they could see the top of the stairs right before them. Once they made their way to the top, the two of them headed straight for where Diego should be. However, the two of them were cut off by two more duelists.

"Now what?" Cray complained as they were both faced with two similar duelists, one with blonde and another with brunette hair, for they were twins.

"This is as far as either of you go."

"Yeah. We can't let you through."

"And you two think you can stop us?" Yukina said.

"Two heads are denser than one." Cray said. Despite that, the twin duelists appeared to be standing in their way. "We don't have time for these losers. You go on ahead, Yukina. I'll take care of these losers."

"Right." Yukina said as she forced her way through.

"No you don't!" The twins tried to stop her, but Yukina jumped right through them and was able to keep going.

"You get back here!"

"Hey! Don't ignore me!" Cray called as he was serious.

"You don't really think you can take on both of us, do you?"

"We've read your data. We know how your deck works."

"Don't go thinking you know my deck. No one can prepare you for the likes of me." Cray said as he seemed serious and isn't going to let anyone get in his way. As for Yukina, she kept on going down the hall until she could see it coming in sight. At the end of the hall was a set of doors and she just knew that had to be it. When she reached those doors, she busted them opened and was faced with...him.

"Hello, Yukina." Diego greeted.

"I finally found you, you rotten snake in the grass." Yukina said.

"I'm quite pleased you made it this far, despite using your friends as a catalyst." Diego said. "It's a true showing of your skills as a duelist, but I guess I shouldn't be surprised given the circumstances. Why don't you have a seat and we can talk all about it?"

"I got nothing but one thing to talk to you about. Where is the card?!" Yukina said. "I'm here for the card you stole?!"

"Stole is such an ugly word." Diego taunted. "Life Destroyed really didn't belong to anyone. It was just sitting away until some could came to claim it."

"Don't play around with me! Do you not know of the danger you're bringing or do you just don't care?!" Yukina said.

"I'm well aware of the power that card holds, but it's not as bad as you think." Diego said. "All one would have to do is surrender themselves to the darkness of that card. Claim control of the power by giving in to the darkness. That is what's happening with him as we speak."

"Him?!" Yukina said as she pictured someone who is mad, dangerous, and could be the very vision of sinister. "Don't be crazy, Diego. It's called Life Destroyer for a reason."

"Yukina, you don't seem to understand the kind of power yourself." Diego said as he doesn't seem concerned about the danger he's bringing. "Every card has a hidden power in it, and that power can be brought upon by the strength of the duelist. This card is just a little different because the power is too great for ordinary man, but the one who does hold it can hold unspeakable power. In fact, I thought you of all people would understand that." He said as he stood up. "Why do you think I'm targeting you in the first place? Under normal circumstances, I would have thought you were just a little bug that would have been annoying, but a minor nuisance and can easily be removed. The reason I'm targeting you is because I thought you really understood all of that and can do that with your own deck. I believe you could really be a threat to my plans."

"You're right about that and I will." Yukina said as she got ready to take action.

"Of course, there is another option. Join forces with me." Diego offered with Yukina surprised he offer that. "The potential and power in these cards are greater than humans could imagine, but you understood that. It would also put an end to all of this fighting. That power brought out could actually help you claim the world. It's not just a fantasy. Join me and I can show you the limitless possibilities and potential!"

"You're right. There is greater power in dueling than people think, but you're out of your mind if you think I would ever join you!" Yukina claimed as she thought about someone else who knew what that power was really meant for. "I know what this power is for, and I'll never join the likes of you who will use it just to destroy everything!"

...

The Training Area

"Heatsoul General, attack!" Kent ordered as his monster blasted every monster it could.

"Seasonal Spring Enchantress, attack!" Cindy called as she had her own monster use a little magic and blasted other monsters.

"Gladiator Beast Augustus, take them down!" Felix called as he had one of his gladiators attack and destroyed the final set of monsters that got in the way. It took some doing, but they managed to get all the enemy duelists out of the way. "That takes care of them. Come on. We've got to find Yukina and Cray." Cindy and Kent agreed as the three of them moved as fast as they could to find their friends.

...

Cray

"Go now, Storm Dragon! Get these two fools out of my way!" Cray called. He used the power of the dragon that Diego himself gave and was able to blow the twins away with both of them loosing. "I told you that no one could prepare for the likes of me." Once he was done with his opponent, Cray got moving to try and catch Yukina. What no one realized was all this dueling was stirring something below the base...and that something had the card they were looking for.

...

Yukina

"No more stalling, Diego! Tell me where that card is!" Yukina called. "It has to be sealed away! It's too dangerous!"

"You're rather impatient." Diego said. "You really have nothing to fear. In mere moments, the card will be under our control."

"Even if you could control that card, you'll still just use it for the wrong reasons." Yukina said. "You don't know what you're doing. That card was sealed away for a reason."

"Only because no one could control it's power until now, but I found the one who can use it's power." Diego said. "Yukina, do not make the same foolish mistake as before." When he said that, it made Yukina angrier. As this was going on, what lied below was starting to react and seemed mere seconds away from awakening. "That power shall be released! You're a fool to let something like that go to waste! The power to obtain world domination is within our hands!"

"You're out of your mind!" Yukina shouted as she charged right at Diego. That was when it awakened. The evil power Diego had woke up and power surged right through the building. Just as Yukina reached Diego, the power burst right from where she was standing and knocked her back. This wasn't good at all. The whole building began to shake as the terrifying power that Yukina was worried about has been released. When Yukina pulled herself together, she saw the dining hall was a wreck. "What just happened?"

"Hehehehe..." Yukina looked around and soon spotted the shadow of some giant standing before her. Then, it just simply faded away and saw someone else standing there. It was a guy about her age with tan skin. He had white hair in a scissor-cut style. He wore black leather clothing with the face an omni printed on his sleeveless top. He also had a sinister grin on his face. The look in his eyes just said this guy was trouble.

"It's you!" Yukina said.

"It's been a long time, Yukina!"

"Raika!" Yukina called. Faces from Yukina's past are starting to come to light, and one of them happens to be the danger she was weary of.