Thanks to Dimension Linker, Yumi was able to uncover the true purpose of the wristband Viper had given him, and once the function was laid bare, the device's design immediately became far uglier than it had looked at first glance.
To put it simply, the wristband was not merely some harmless tool used to monitor the students during duels, but a device that enhanced the drawing of Spirit Energy from a duelist during their duels, and once that energy was extracted, it would be siphoned away and transported toward a specific location somewhere on the island.
Once Yumi confirmed that much, he no longer had any reason to keep pretending he had not noticed anything strange.
He let Dimension Linker begin hacking into the wristband at once, and from there, she started tracing the system back to its source, following the flow of stolen Spirit Energy like a thread being pulled through a maze.
It was not particularly difficult for her, either, not after Yumi had made her a Link Monster and then pushed her power far beyond what her original counterpart had ever been capable of, granting her all eight link markers. With her upgraded abilities, piercing through a system like this, especially one designed in the early 2000s and nowhere near as advanced as something made by someone like President Kaiba, was honestly not much of a challenge.
It only took her less than an hour to locate the exact destination where the Spirit Energy was being sent.
After that, she went a step further and created a chip that would allow the stolen Spirit Energy to be redirected straight into Yumi's wristband now that it had been repaired and altered. Of course, for that to work properly, it also needed to be placed in the correct part of the system, which meant someone had to place it there without drawing attention.
So, to make that possible, Yumi created an Overtime Kuriboh and directly linked it to Dimension Linker, allowing her to guide the small creature to the proper location while keeping it out of sight.
Yumi had no intention of stopping Viper from stealing the students' Spirit Energy just yet.
He did not remember this part of the plot clearly enough to interfere recklessly, and if he got too involved right now, there was a very real chance that Jaden would lose the growth moment he was supposed to have, which would only end up shifting more of the trouble onto Yumi's own shoulders.
He wanted a brighter future, not a future where he stole the role of the story's main character and dragged the entire plot away into unknown waters.
That was not what he wanted. He did not want to become the center of everything. He only wanted to make sure the future became better.
"Also, what was that all about? You didn't have trouble breathing after beating an opponent before."
Celina's voice broke through his thoughts, and Yumi looked over to see her sitting cross-legged on the top bunk, watching him with a curious expression that was only half teasing and half concerned.
"...That," Yumi began, though he immediately found himself at a loss for words, because it did not take a genius to realize that what had happened was not something he could explain easily, especially not in a way that would sound normal.
He himself was not exactly the kind of person who thought of himself as a hero, and he certainly did not see himself as the sort of upright protagonist who would charge forward with justice in his heart, but at the same time, he did not consider himself a monster either.
In this world, after all, things were decided by card games, by duels, by the strange rules this place insisted on following, and even if death could be brought about through dueling, that kind of thing was still something that sat heavily in the back of his mind whenever it came too close.
He had Kaito's blood on his hands. And seeing Jaden and Jesse collapse like that had stirred up the same ugly feeling buried deep inside him, and the same unwelcome reminder that some things were easier to accept in theory than they were in reality.
"It just happened," Yumi said at last, deciding that the simplest lie was often the easiest one to survive on.
Because the truth, that he had traveled to another dimension and accidentally killed someone in a duel, was not something he wanted to explain.
"Yeah, right..." Celina muttered, clearly not believing him at all, though after a brief pause, she eventually chose not to push the matter any further. Her roommate did not seem like he wanted to talk about it, so she decided to leave it alone for the time being.
Over the next few days, the other students at the school were given the same wristbands by Viper, and before long, Yumi could feel the flow of Spirit Energy from all over the island beginning to gather and move in a way that made the whole place feel strangely tense beneath the surface.
Thanks to Dimension Linker, he had her reduce the force of the Spirit Energy being drawn from the students so they would not collapse from exhaustion the way Jaden and Jesse had the other day.
In the end, the transfer was split into three-fourths and one-fourth, with three-fourths being sent to him and the remaining one-fourth being allowed to continue onward to its original destination so that Viper would not immediately become suspicious.
At the same time, Yumi tried to find Midori so he could warn her about the wristbands, but after searching for a while and asking around, he eventually learned that she had gone off the island on personal business again and that she was nowhere to be found.
"When the world needed her the most, she disappeared," Yumi muttered dryly as he walked past the infirmary and saw a line of exhausted students filing out one after another.
With the reduced amount of Spirit Energy being drained from them, the students did not collapse outright, but they still looked drained, sluggish, and miserable.
Still, unless someone was foolish enough to keep dueling when they could barely stand straight anymore, then fainting was their own fault at that point.
As the number of students suffering from severe fatigue continued to rise at an alarming rate over the following days, concern gradually spread throughout Duel Academy. What had initially been dismissed as simple exhaustion from an increase in dueling slowly became impossible to ignore.
Naturally, Jaden's group became increasingly worried.
Now joined by Jesse and Jim, the group began piecing together everything they had seen over the past few days, comparing each strange incident until a pattern slowly began to emerge.
It did not take them very long to notice that every student suffering from this mysterious fatigue had one thing in common.
Every single one of them was wearing the same duel wristband.
The very wristbands Professor Viper had distributed.
Not only that, but the devices could not be removed once equipped, almost as though they had been designed to stay attached regardless of whether the wearer wanted them on or not. Coupled with Viper's encouragement for everyone to duel as often as possible, the situation became more suspicious with every passing day.
Then there was the professor himself.
Despite being one of Duel Academy's newest faculty members, Viper rarely appeared around campus unless it involved promoting his duel program. He did not taught any actual classes, rarely interacted with students outside organized events, and seemed to vanish whenever anyone tried looking for him afterward.
To Jaden's group, all of those clues pointed toward the same conclusion.
Professor Viper had to be involved.
Whether he was directly causing the students to collapse or merely hiding something, they were convinced he was the mastermind behind everything that had been happening on the island.
From their perspective... The evidence lined up almost perfectly.
Of course, the truth was a little more complicated than that.
Viper himself was hardly the true mastermind. He was merely a pawn, a man unknowingly dancing in the palm of someone else's hand.
Hidden far from everyone's sight was Yubel, who had returned to Earth after drifting through space for years, her body heavily damaged and her strength reduced to a fraction of what it once had been. Desperate to restore herself, she manipulated Viper into collecting vast amounts of Spirit Energy from the academy's students, using him as little more than a convenient middleman while keeping her own existence hidden.
But if someone were to follow the flow of that stolen Spirit Energy one step further... They would discover an even stranger truth.
Most of it was not even reaching Yubel.
Thanks to Dimension Linker's modifications, the Spirit Energy being siphoned from the students was intercepted midway through its journey. Roughly one-quarter continued toward its intended destination so nothing appeared unusual from Viper's perspective, while the remaining three-quarters quietly changed course before disappearing into Yumi's repaired wristband and into his body.
In other words...
Viper believed he was achieving his goal perfectly.
Yubel believed all the Spirit Energy was being transferred to her.
Meanwhile, Yumi sat comfortably in his dorm room, contributing absolutely nothing to the project while quietly receiving the majority of the profits.
To put it simply...
Viper was the villain that everyone kept their eyes on.
Yubel was the manipulator, manipulated the other party like a puppet, pulling the strings from behind the curtain.
And Yumi was the shameless bystander standing underneath the stage with a large basket, calmly collecting most of the money that fell out of everyone else's pockets.
Even the other Big BOSSES throughout Duel Monsters history would probably stop for a moment, stare at this arrangement, and quietly start taking notes.
After all, it wasn't every day someone managed to profit from another villain's evil scheme without actually doing any of the evil scheming themselves.
From a certain point of view, the whole thing was simply too heartless.
If Yubel ever found out... She would probably forget all about reuniting with Jaden for at least five minutes just so she could hunt Yumi down first.
Yumi let out a long, lazy yawn as he lay sprawled across his bed, one arm tucked behind his head while the other rested over his stomach. The warm afternoon sunlight drifted through the dorm room window, creating just enough warmth to make moving feel like far more effort than it was worth.
At that moment, he genuinely did not have a single care in the world.
"Yumi... you seriously aren't going to help us?"
Rio's worried voice reached him from nearby, pulling his attention just enough for him to lazily turn his head. She was leaning lightly against the side of his bunk, her magenta eyes fixed on him with a mixture of concern and disbelief, as though she still could not quite understand how someone could remain this relaxed when the situation outside was growing more and more serious by the day.
Ever since her brother had pushed himself too far during the recent duels and ended up confined to an infirmary bed, she had become noticeably more anxious whenever the conversation drifted toward Professor Viper, and that concern had only deepened as the strange fatigue affecting the students continued to spread.
"Yeah, you guys have got th-"
Before Yumi could even finish his sentence, a foot suddenly connected with his side.
It was not especially hard, more of an annoyed nudge than a real kick, but it was still enough to interrupt him and make the rest of his words die in his throat.
"Stop being deadweight already!" Celina snapped, pulling her foot back and crossing her arms with an irritated huff. "You're literally the strongest person here, so start acting like it instead of lying around while everyone else does all the work!"
Yumi simply rolled onto his other side without bothering to sit up, then tilted his head so he could look at her with the sort of smug, infuriating smile that seemed to exist for no other purpose than to test people's patience. Judging by the slight twitch at the corner of Celina's eye, it was working exactly as intended.
"Don't worry," Yumi said in the same calm, lazy tone as always. "If you guys somehow manage to get your asses kicked, I'll just clean everything up afterward."
Celina: "..."
Rio: "..."
Celina's eye twitched once more, while Rio let out a quiet sigh that sounded like she had long since accepted that this was just how Yumi talked whenever he was being especially unbearable.
They were no longer surprised by answers like that.
Rio remained quiet for a moment longer before speaking again, her voice gentler this time, though still threaded with concern. "So... if we lose, and you end up having to duel Professor Viper yourself..."
She paused, looking at him carefully, her calm magenta eyes meeting his golden ones with a seriousness that made the room feel just a little quieter than before.
"Would you lose?"
For a brief moment, silence settled over the room.
Yumi looked back at her without saying anything, his expression unreadable at first, as though he was considering whether or not he even wanted to answer properly. Then the corners of his mouth slowly curved upward, and a confident grin spread across his face like it had been waiting there all along.
"Nah, I'd win."
Rio blinked once, then a soft smile naturally formed on her lips, as though his answer, ridiculous as it was, had somehow managed to reassure her anyway.
Celina, meanwhile, stared at him for several long seconds before clicking her tongue with obvious irritation. "Why do I feel like you're saying that just to sound cool?"
"I have no idea what you're talking about."
"...Liar."
She kicked him again, though this time it was even less serious than before.
After exchanging one last exasperated look with him, the two girls eventually gave up trying to recruit him any further. There was simply no moving his lazy ass unless he decided he wanted to move himself, and they both seemed to understand that well enough by now.
Before long, Rio and Celina left the dorm to regroup with Jaden and the others so they could continue investigating Professor Viper together, leaving Yumi behind in the quiet comfort of the room.
Several peaceful minutes passed.
Then, all of a sudden. A soft paw lightly smacked him on the forehead.
Yumi slowly opened one eye.
The fat orange cat was standing right on his chest, looking down at him with an expression that somehow managed to convey disappointment despite the fact that it was, in fact, just a cat. After making sure it had his attention, the little creature raised one paw again and pointed toward the dorm window with deliberate insistence.
Too lazy to get up himself, Yumi simply waved a hand.
"Effect Veiler."
A small flash of light appeared beside the bed, and the spirit girl materialized there with her usual gentle expression, her flowing water-like wings shimmering faintly in the light. She glanced between Yumi and the window, then let out a small sigh.
Still, without complaint, she floated over and peered outside.
A few moments later, she turned back toward Yumi and gestured toward the window.
There, standing outside the dorm and looking around as though she was searching for someone, was Kazuko.
"Guess I have to get up after all." Yumi let out another sigh before reluctantly climbing out of bed.
A few minutes later, the peaceful beach surrounding Duel Academy became the scene of a rather absurd sight.
Kazuko was sprinting across the shoreline with steady, rhythmic breaths, her feet kicking up little sprays of sand with every step while a thick rope wrapped securely around her waist tugged behind her. Attached to the rope was a large training tire that scraped across the beach with a heavy, dragging sound, though Kazuko herself did not seem even slightly bothered by the weight.
Seated comfortably on top of that very tire was Yumi.
He leaned back with his legs crossed, one hand resting near the edge of the tire while the other remained loose at his side.
"So," Yumi asked lazily while enjoying the ride, "how's Duel Academy treating you?"
"It's been great!" Kazuko answered cheerfully without slowing down in the slightest, her voice bright and energetic despite the fact that she was currently running while hauling several times her own body weight across the beach. "Although... I do think some people here are kind of weird."
"Weird how?"
"I mean..." She tilted her head slightly as she kept running. "Some students actually passed out after only two duels."
She sounded genuinely confused, as though this was a deeply unfair injustice that should be corrected immediately.
"If drawing cards is enough to make them collapse, then they must be absolutely terrible during P.E."
Yumi decided not to point out the real reason for that.
To be fair, after her own second duel, Kazuko had admitted to feeling somewhat out of breath, but that was where the similarity ended, because instead of collapsing like the other students, she had simply eaten an enormous meal, taken a four-hour nap, woken up completely refreshed, and immediately gone looking for two more opponents to challenge.
If the exhausted students stumbling out of the infirmary ever learned about that recovery speed, they would probably cry tears of envy on the spot.
Seriously...
Are you absolutely sure she's just a high school student?
Yumi, however, was hardly surprised. As her older brother, he knew exactly why Kazuko's physical abilities were so absurd.
From a very young age, both Kazuko and Momoyo had been trained in the Kawakami Style under the guidance of their grandfather, enduring years of relentless physical conditioning that would have made most adults surrender within a week.
Yumi had tried joining them once.
Only once.
He simply lacked the talent for that sort of physical training, and perhaps, more importantly, he lacked the patience to keep throwing himself into it when there were clearly other paths available to him.
Fortunately, their grandfather had noticed that rather quickly and never forced the issue. Unlike his sisters, Yumi was never expected to continue pushing his body beyond its limits.
That decision became even easier after Yumi demonstrated his ability to summon Duel Monster Spirits.
The old man had watched quietly for several minutes before reaching a very simple conclusion. That Yumi was a Special Attacker, not a Physical Attacker like his sisters.
And he is most likely related to that woman from the Izinski. Still he is his grandson now so he didn't pay much mind to that old family.
As far as his grandfather was concerned, Yumi belonged in an entirely different build.
Trying to force him to compete with two monsters who had invested every stat point into Strength and Endurance would simply be a waste of everyone's time.
After all...
Why teach the boy to throw a punch...
When he could just summon a spirit to do the punching for him?
With absolutely nothing better to do, Yumi remained comfortably seated atop the tire while Kazuko continued dragging both it and him across the sandy beach for another several hours as part of her afternoon training.
The wind from the ocean brushed past them in cool waves, mixing with the sound of footsteps, the scrape of rubber against sand, and Kazuko's steady breathing as she kept moving without a single sign of complaint.
Only after finishing her run did she finally slow to a stop.
Without wasting even a minute, she headed toward the forest beside the Slifer Red Dorm with Yumi casually following behind, his hands in his pockets and his expression as relaxed as ever. After searching for a short while, Kazuko eventually found exactly what she had been looking for.
A massive fallen log.
Without the slightest hesitation, she bent down, wrapped both arms around it, and hoisted the enormous piece of wood onto her shoulders as though it weighed little more than a school backpack. Then, with the same determined energy as before, she simply continued training as if carrying around giant pieces of timber was a perfectly ordinary thing to do.