Is this the poker world?Ada thief!

However, compared to the commotion inside the iron gate, Judai's attention was more focused on Amon's outstretched arms—specifically, his left arm.

Although it was late and there was little lighting on the weekend, and even the light reflected from the moon was mostly obscured by the not-so-thick but not-so-thin fog around the pond, Jaden still managed to see Amon's left hand clearly—several strangely shaped "scales" were growing on the skin of his arm, exactly the same as the scales on Professor Cobra's hand in the past!
"That is!?" Jaden stepped forward nervously. "Amon, could it be that you... you've become Yubel's puppet again?"

"What? Does this guy have some kind of bad luck? How come he's so easily affected by other people's mental abilities?" Manjoume, who was completely unaware that he was the character who was affected by mental abilities the most times in the entire GX series and even the entire Yu-Gi-Oh! series, in another timeline, complained.

(Light Wave, Duel Zombies, Evil Orb, Darkness Illusion)
“Jūdai, Manjōme, I am very grateful to you both for saving me from being controlled by others in the past.” Amon looked at his arm, but did not care about the strangeness that had appeared there. “But I, who am standing here, have not been controlled by Yubel or any other being. My actions are entirely of my own will.”

"As I said before, my purpose in returning to this world is not to rescue John Anderson. When I came here last time, although I did not explore, the equipment I carried, with the help of the protective measures completed by Daichi Misawa, collected a special signal of this world, which allowed me to find the card that was sealed here."

Judai and Manjoume didn't pay attention to anything else in Amon's words, but instead exclaimed in surprise in unison, "How could someone actually get Misawa's name right?"

("So you all know you misspoke about my name, right?!" Misawa, blushing because his hand "accidentally" touched Tanya's while talking, turned his head away shyly and subconsciously made a sarcastic remark to the air.)
O'Brien was more serious, or perhaps because he had only been at the Duel Academy headquarters for a short time and hadn't yet realized how difficult it was to pronounce Misawa Sora's name correctly: "So, you hitched a ride back to this world just to get here?"

“I didn’t have high hopes to begin with, but maybe it’s some kind of ‘observer effect’ principle? When I became aware of this place and wanted to find it, I followed you all to this vicinity without leaving the group, and even the card sealed here started to call out to me.”

“Although I am very patient, the cards here are calling to me so urgently that I could not wait any longer and found this place overnight.” Looking back at the sealed iron gate, Amon’s tone became quite regretful. “But unfortunately, something very important is still missing to break the seal here.”

Turning back to look at Jaden, Amon's eyes held something special this time. It only appeared when he looked at Jaden and Manjoume, but not when he looked at O'Brien. Jaden couldn't quite put his finger on what kind of feeling that look gave off.

—If I had to put it that way, it's like a child looking at a toy they really like, but having to trade it away in order to get something they like even more from someone else.
"Yuki Judai!" Calling out Judai's name, Amon raised his left arm, generously displaying the scales on his hand, and said, "I think what [Yubel] said when he controlled my body was correct. At that time, you did manage to free me from [Yubel]'s control by severing the darkness in my heart, but unfortunately, it was all in vain, because everyone has darkness in their heart that cannot be eradicated. The most one can do is to face one's own darkness with equanimity."

"My darkness has awakened once more, along with the lingering aura of [Yubel] on me. I think that's why its scales have reappeared on my hands—it's the embodiment of the darkness within me that I cannot avoid and must ultimately confront!"

"I want to obtain the card here, and the power of that card. To do this, I must offer a sacrifice—and there are not many people in the world who meet the requirements. You and Jun Banjou are among them!"

“The rare talent—the power of the ‘Elf Master’—if you defeat you here, these locked doors will surely open.” Amon said, unfolding his Duel Disk. “To attack a fellow comrade, pointing a gun at a fellow comrade is absolutely forbidden, even without the safety off, let alone unfolding your Duel Disk!” O'Brien, being well-trained, immediately drew his own Duel Disk from his waist, but not in its Duel Disk mode; instead, he aimed the gun directly at Amon. If Amon made any move, no one would doubt whether O'Brien would fire.

"We have no reason to duel, Amon." Jaden didn't want to duel Amon. All he wanted now was to lead everyone back to the human world. He didn't want to lose any more of his comrades. "Duels in this world can kill people. I don't want to see any of my comrades die!"

"So you think you've got me cornered, Jaden? You're completely oblivious to your own arrogance, like someone who doesn't see the trash and won't pick it up," Amon said calmly. "And, no reason? I think my reasons are sufficient. I'll add another one if you need—"

"All for the Gallam Foundation? No, now that I've faced the darkness within myself, it's time for me to face my true self. Let's duel! For power! The power to become the 'Overlord'!"

"A duel? Have you gone mad?!" Manjoume roared. "'For power'? What kind of reason is that? And you want to become a 'tyrant'? Have you lost your mind?!"

"Nonsense, I can't understand it!" he said, turning to leave. "Let this idiot stay here and fend for himself. It's better for everyone if we give him up."

"but--"

Judai wanted to say something more, but when he saw Manjoume about to leave, Amon reacted even faster: "That won't do. I never said you could leave here."

The surrounding fog suddenly thickened at a visible speed, and O'Brien immediately fired in Amon's direction. Although it was only a guess that Amon might have done something, this was probably enough for O'Brien to take action for the safety of the people present.

However, something was faster than O'Brien. It was a sword formed from mist that suddenly appeared in the mist in front of Amon and cut through the card that O'Brien had fired. The card, "Volcano Bullet," was cut open and fell to the ground, while a materialized sword-wielding warrior appeared in front of Amon.

Manjoume recognized the guy because Amon had used that thing when he fought him in the past, and that thing was actually the "medium" that Yubel used to control Amon.

—Duel Monster Card, [Lord of the Mist]! (End of Chapter)