I never really intended for this story to be a mystery, but the actual motives of the antagonists have always been pretty murky. Here is where I lay them out, so that you all can see just what's been going on behind the scenes to inspire what you've seen.

I won't pretend like I knew this was what was going on from the first.

But I do think it explains things rather nicely.

.

"Speak, golden ghost. I know that look."

Yugi was scowling at the floor, his brows knitted together, as he mulled over something of thunderous importance. It took him quite some time to speak. Finally, after a short eon, he said: "I think I am finally beginning to understand the aims of our enemy."

Kisara leaned back. "Tell us."

"I have already spoken on this subject with Mister and Missus Yagami," Yugi said, gesturing. He turned to Seto. "I believe that Gozaburo Kaiba's target is not young Sotaro at all. I think it is you."

Yuki and Kohaku both nodded.

Seto's eyebrows raised. "Oh?"

"I think," Yugi went on, "perhaps, that his original aim was to take Sotaro for his own devices, to craft himself an heir befitting his legacy, much as his counterpart here did with you. However, I believe that, when he beheld your empire, he changed course. I think he wishes to take your Kaiba Corporation for himself. You were meant to die that day, and the fact that you lived has him throwing ever more resources into the singular task of killing you. A sunk cost fallacy, perhaps. It is a matter of pride now. He cannot walk away until he has your head on a spike."

Seto growled, low in his throat. "Everything I learn about this man disappoints me."

Kisara smiled dotingly at her champion. Then she turned back to Yugi. "What new insight have you found?" she asked. "What is it you believe you now understand?"

"The spell which I used to bring the Yagamis into this world," Yugi said, "requires blood to hold the traveler and secure their survival. This is easy enough to procure on one side. The home side, if you like. But on the other, it is much . . . stickier, if you will pardon the pun. Typically, it involves weeks of divination and elaborate planning with another spell-worker on the other side. I was able to circumvent many of the usual complications, but I am unique in that regard."

Kisara didn't look surprised or confounded in the slightest. "A sanguine arcanopathic loop," she said. Yugi stared for a beat, then nodded emphatically, obviously surprised but not displeased.

"Yes! Precisely!"

"A what now?" Kohaku asked, as he was confounded.

"Blood carries a person's essence more densely than almost any other part, in the realm of magic," Kisara said. On the table near where she sat, there sat cups and saucers. She reached over and took two cups; she set them some distance apart. She then took a stirring spoon and set it in between the two cups, like a wall.

"Uh . . ." Kohaku leaned forward, intent on finally understanding what he'd been through.

"Here is one world," the queen said, gesturing to one cup. "Here is another." She gestured to the other.

"Okay," Kohaku said slowly.

Kisara tapped the spoon. "Between these two worlds is a barrier, not unlike the plane where I have made my kingdom, which you so recently visited. To cross that barrier, and travel from one world to another, is perilous to living things." She eyed Kohaku to make sure he was paying attention; he was. "Not only is breaching the barrier normally impossible, but even if you managed to do that you would find yourself in immense trouble thereafter. Imagine walking through a door, only to fall head-first into an ocean."

Kohaku rubbed his chin. "You'd need a ship," he said.

Kisara smiled. "Precisely." Kohaku's face brightened. "A sanguine arcanopathic loop is . . . the shipwright, in this metaphor. It is the process by which you forge the protection necessary to survive the barrier." She tapped the first cup again. "The first half of the spell is cast here, In your home world, which you might think of as the harbor from which you depart. The traveler's blood is used to complete this spell. To fuel it, if you like, and to . . . calibrate it to you, specifically." She tapped the other cup. "Then, to complete the loop, the same spell must be completed at your destination, to provide you with a lighthouse."

"You need someone who shares your blood," Yuki said.

"Need?" Kisara looked surprised. "No, it isn't necessary. But it is safer."

"Yugi used their blood for the first spell," Mokuba said, "and mine for the second one."

Kisara nodded. "This is the . . . optimal method," she said. "You are related, directly by blood, to all three travelers." She pointed to the three Yagamis in turn. "This provides the strongest, most stable connection of all. Travel is rendered nearly effortless. The worst one might suffer is nausea, or a light headache."

"Huh." Kohaku frowned. "So, all these people that Gozaburo Kaiba is sending after us. They're from back home? From our world? Is he using this same spell to send them here?"

Yugi nodded. "I believe that he is," he said. "I also believe that he is using a much more dangerous, much more demanding variation of the spell."

"Sacrifice?" Kisara asked; Yugi nodded. "Naturally." She leaned back into her seat and stared off into the distance for a time. "If the loop you have traveled is a cruising ship, then he is using a training shuttle. The more blood channeled into the spell, the more fortified the traveler becomes. Not just against the threats present in the barrier, but against all threats."

"More blood makes them stronger?" Yuki guessed.

"Yes." Kisara nodded. "Stronger, more resilient, more difficult to counter. That is the nature of this man: he is sacrificing human lives to send his soldiers after you. However, since he is using mundane soldiers, so to speak . . . by which I mean to say, those without knowledge in the ways of magic, he is relying purely on brute force. What magic they use is . . . crude."

"Crude, perhaps," Seto put in, "but effective."

"Against you and your court, perhaps," Kisara said, "but not against me."

Far from taking offense at this proclamation, Seto seemed quite pleased by the queen's answer. He chuckled to himself, waved dismissively, and offered no rebuttal.

"This leads to what I believe I now understand," Yugi said. "The penalty game this boy," here he gestured to Masahiko, "has described . . . is called mind crush."

"I'm familiar with it," Seto said, rather darkly.

"Perhaps," Yugi said, "but I believe that your heart and mind were not nearly as confused or muddled as those of the man I know. Or else the version of me that you know was not so . . . forceful. In the case of my own memory, it took Seto Kaiba six months to reconstruct himself."

Seto looked surprised, and more than a little superstitious.

Masahiko flinched. "It hasn't been that long."

"I believe that the timelines of our world are converging," Yugi said. "I believe that, while I am the . . . ahem, Yugi that you know, I exist in your future." Masahiko looked confused, and angry. "Forgive me for saying this, but it is a minor factor in all this. Magic and linear time rarely get along. Complications like this are quite common, actually."

Kisara nodded. "You speak true."

"In any case," Yugi said, "while Seto Kaiba pieces together his heart, he is vulnerable. Not only to attack, but to . . . infiltration. Possession." He looked at Kisara. "I think this boy is right. I think he was meant to fail. I think he was meant to die, and that his killer was meant to complete a loop. For his brother."

Kisara stiffened. She uncrossed her legs and shot to her feet. "You mean to say that Gozaburo Kaiba meant to use Seto Kaiba as a weapon against his own counterpart. To wear him like armor and lay siege to this world. He would transfer his own consciousness into his own son, abandon his old body and take up his own heir's identity, and wage a new war."

Yugi nodded. "I do."

Seto's eyes narrowed. "What better way to replace me," he murmured, "than with me? I am weak. Compromised. What chance would I ever have against myself at full strength? At more than full strength?" He looked at Masahiko. "Your brother is younger than I, but from what you have told me, he is more acclimated to my predecessor's lessons than I ever was."

"I think so," Masahiko said.

"I will not pretend to know why," Seto continued, "but it doesn't matter. Once I was dealt with, he would be in the perfect position to usurp me."

"My god . . ." Yuki whispered.

"He failed, though," Kohaku said. "If that's his plan, it didn't work. He has to know it didn't work, right? He's on the back foot now, isn't he? I mean. Nobody else died. So that's good, isn't it?"

"In one sense, yes," Seto said, "but it also means we will soon be dealing with a desperate man. He will continue to grow angrier, and lose more patience, the longer we stave him off. And while that means the likelihood that he will make mistakes is higher, it also means there will be no way to predict him."

"That, little prince," Kisara intoned, "is why I am here."