After the Darkness Incident, both the school and the world settled into peace.
Hikaru finally had time to do what he wanted.
Between his studies, aside from a new round of alchemical experiments, there were a few places he wanted to visit.
First, the Gladiator Beast Dimension, a place he had wanted to go to many times but had been held back from each time by one emergency or another.
Second...
The World of Selfless Art!
The dimension most likely to contain information about the "red light"! The dimension that had been struck head-on by the red light!
Now that Hikaru's spirit adaptability had reached Level 9, he had successfully created his own Philosopher's Stone, becoming a genuine top-tier alchemist, and he was also a human who had been directly exposed to the red light. Naturally, he wanted to investigate.
But he wasn't the type to court death for no reason, so preparation came first.
He started by throwing test dummies through the portal. After retrieving one a minute later, it was completely unharmed.
Clearly, that world held no instantaneous physical threats.
He ran more tests, leaving dummies inside for three or four days, setting up recording equipment. The results were always the same: nothing abnormal.
It was as if the other side was just an ordinary, mundane gallery.
But the emptiness of that gallery, the deathly silence, the total absence of even spirits, and the way the place seemed alive, looking different depending on when you observed it, all reminded Hikaru and Tierra that this dimension was anything but calm.
His "duelist's instinct" was screaming at him: don't do it!
He had defeated Darkness and developed immense mental resilience, yet this strange feeling persisted. That dimension was too dangerous for living things.
Once he realized this, Hikaru stopped rushing.
Strong as he was, and capable of minor risks, he wasn't suicidal.
Fine.
Hikaru gracefully backed down.
So he shelved the idea of entering the World of Selfless Art anytime soon and instead visited the Village of Spellcasters to check in with his spirit contact and ask about any new inventions or collectibles.
After that, he stopped by the Spellbook Academy, where he traded his alchemical insights for a few books he had been wanting.
With his spirit adaptability at 9 stars, as long as he wasn't dueling, Hikaru could now traverse dimensions at will. He no longer needed to ration his monthly trips.
He could visit the Village of Spellcasters for research exchanges, study new knowledge at the Spellbook Academy, and explore the Frightfur Sanctuary or Union Hangar with Tierra, collecting new cards along the way.
He could even visit the Magician's Sanctuary freely, without worrying about energy costs.
Of course, the energy fees still applied, but with a freshly minted Philosopher's Stone in hand, this was the time to spend freely. He visited every friend he could reach, greeting them one by one, and seeing if he could pick up a few cards in the process.
And so, Hikaru finally had the leisure to explore dimensions he had never visited before.
This month, the two destinations he chose were...
The Gladiator Beast Colosseum and the Predaplant Planet.
"Let's check out the Gladiator Beast Dimension first."
He called on Gladiator Beast Andal, who hadn't appeared in ages. Life had been comfortable for the one-eyed gladiator lately: no duels to fight, just working, eating, and sleeping at the Macro Cosmos Workshop. Far easier than his old life. He had even put on weight.
But the moment he heard Hikaru was heading to the Gladiator Beast Dimension, he volunteered without hesitation.
The Gladiator Beast Dimension was unique.
Its most defining feature was...
It was a dimension that had once formed an alliance with the Fusion Corps!
Of course.
The Fusion Corps wasn't its only partner.
Anyone who proved themselves exceptional in the arena could earn spirit cards. The Gladiator Beast Dimension didn't follow the standard tribal growth system of other spirit dimensions. Its system was...
Slavery!
Higher-ranked spirits could command lower-ranked ones at will. That was the world of the Gladiator Beasts.
So when Andal heard he could return to his homeland, he was both thrilled and terrified.
But then he thought...
Wait, I have Hikaru with me. What am I afraid of?
All the chieftains combined probably couldn't beat Hikaru... in any category.
The nervous gladiator relaxed at once.
Andal felt reassured, but Hikaru had long since learned about the dimension's peculiarities from him. Thinking he might run into the Fusion Corps again, he decided to bring along a few "good friends" as insurance.
Phantasmal Demons, Earthbound Gods, things like that. Better to have them and not need them.
Once everything was packed, Hikaru stepped through the dimensional gate at the Macro Cosmos Workshop and departed for the Gladiator Beast Dimension.
Meanwhile...
In a distant dimension with no connection to this world.
A place the locals called...
The Standard Dimension.
Yugi Muto bought a cup of ice cream, took his seat in the audience, and watched a rather unusual duel unfold.
Rumor had it this was a duel between the world's "Duel King" and the son of the "former champion" and "entertainment duelist."
To be honest, Yugi Muto's time in this world had been quite pleasant.
The atmosphere here was far better than in his own world. None of the scheming factions, none of the greed-driven politics. All that existed was "entertainment dueling," refined to its absolute peak.
In this world, dueling was a pure form of entertainment. Especially with "Solid Vision technology," performances where duelists interacted with the holograms were a genuine spectacle.
It made Yugi feel strangely at ease.
In his world, every major corporation hired "representative duelists." The duelists on the circuit were less about "heartfelt entertainment" and more like "corporate swords."
He wasn't sure whether that development was a good thing.
Especially with the advent of dimensional travel, those duelists had become interdimensional prospectors, turning the majority of them into people who prioritized profit above all else.
This world, by contrast, felt simple.
At least during his stay, the duelists here seemed refreshingly earnest.
In fact, the duelists in this world, just like those in his own, had only recently learned of the existence of "Synchro" and "Xyz" Summoning. They had only discovered "Fusion" itself recently!
That was remarkable.
Because in the Synchro and Xyz Dimensions, Fusion also existed.
But looking at it from the other direction...
This world could perform Fusion, Synchro, and Xyz. That was something his own dimension couldn't do.
Still, as of now, the dueling here felt rather primitive.
Almost everything revolved around Tribute Summons.
He was eating his ice cream when his hand suddenly stopped.
Hm?
On stage, the young boy's eyes turned red for some reason. His body began to glow with a dazzling light, and then the cards in his hand started to shine, transforming into entirely different cards on the spot.
Yugi's interest was piqued.
He set his things aside and focused on the duel.
The duelist called Yuya Sakaki placed two cards on either side of his Duel Disk. Then, prismatic light and the power of a swaying soul rippled across the world!
This was...!
It hit Yugi all at once.
So that's how it was.
This wasn't the "Standard" Dimension at all!
Even the leaders of this dimension hadn't realized it!
"I set the Pendulum Scale using Scale 1 Stargazer Magician and Scale 8 Timegazer Magician!"
Two towering pillars of light appeared on the field. Beneath them, two magicians floated into the air, and below their feet, two golden numbers materialized.
1 and 8!
A massive pendulum appeared in the sky from thin air, swinging back and forth.
"This lets me simultaneously Summon monsters from Level 2 through Level 7!"
On stage, Yuya Sakaki shouted by pure instinct.
"Swing, Pendulum of the Soul!"
The pendulum began to sway.
Through Yugi Muto's eyes, the entire world seemed to begin swinging.
So that's what this was! He pulled out his own Duel Disk, pressed the button, and watched as a Pendulum Zone slowly materialized on the expanded interface. He understood everything. From this day forward, Pendulum Zones would spread outward from this place to every world, every being! Pendulum had officially entered the usable stage!
His fascination with this world deepened.
"Carve an arc of light across the sky!"
"Pendulum Summon! Appear, my loyal monsters!"
Three beams of light fell from the heavens, crashing onto the field. Three monsters Special Summoned at once!
"Ohhh!" Yugi couldn't help but applaud.
While everyone else stood frozen in confusion, he clapped with genuine delight.
What a performance. So that's how you use it...
He continued watching and learned that when Pendulum Monsters were sent from the field to the Graveyard, they went to the Extra Deck face-up instead, and as long as their Levels fell within the Pendulum Scale, they could be Pendulum Summoned from the Extra Deck every turn.
Fascinating.
Fresh things were always exciting.
Though Yuya Sakaki won by simply leveraging Pendulum Summoning's raw properties, without any elaborate tactics or applications, Yugi still felt the thrill lingering long after the duel ended. He didn't even care that his sundae had melted.
Beating out every other competitor and coming to this dimension as a card designer had been the right call!
He had witnessed the birth of Pendulum Summoning with his own eyes!
"So that's... Pendulum Summoning."
At the same time, inside this dimension's Leo Corporation, a young man wearing glasses and a scarf pushed his frames up with a light touch, watching the screen before him without blinking.
He was the "leader" of this dimension. Declan Akaba, son of Leo Akaba.
Beside him, reflected in the surface of a nearby machine, a red-haired maiden sat with her eyes closed. She made no sound with her lips, yet her voice carried through.
[As I told you, a key to unlock the Pendulum of the Soul lies hidden within that human's body. Once he activates that key, humans like you who possess special particles will be able to wield this power, much like an open-source program.]
Her voice drifted in and out, barely there.
[Mortal. You saw it too, didn't you? That interdimensional duel. Do you believe you could defeat the human called Hikaru Amagi?]
Declan pushed his glasses up again.
The duel against Darkness had been observed by virtually every higher being. Naturally, the strange "goddess" at his side had the privilege of watching as well, though she had merely observed without offering any commentary.
That duel. If it were the current him, he would have had absolutely zero chance of winning.
The gap was too vast.
That Hikaru Amagi's mastery of the path of Fusion surpassed his own tenfold at the very least.
How could he hope to catch up in a short time by learning Synchro, Fusion, and Xyz from other dimensions?
But...
The power of the Pendulum was a force inherent to the humans of this world!
With that power, closing the gap or even surpassing humans from other dimensions in a short time was far from impossible!
He still hesitated.
The hesitation wasn't about learning or advancing Pendulum power.
Was that Hikaru Amagi really what this goddess beside him claimed?
Several months ago, this entity had appeared in their world. She struck a partnership with him and provided a wealth of cards she called the "Power of the Duel Terminal Planet," spanning Synchro, Fusion, and Xyz. He had distributed these cards across the schools of their world, and the results had been promising. Talented students were being fast-tracked in great numbers.
But what concerned him more was the other god she spoke of: Tierra.
Tierra. The god who despised life. God of machines. God of demons. God of reincarnation.
Once fully revived, she would inevitably reset the ecosystem, creating life that suited her preferences.
And her chosen one was the human called Hikaru Amagi.
During that duel, watching Tierra's cataclysmic effect, Declan had been deeply troubled.
After all, it seemed like a first-turn Fusion Summon of Tierra with 10 materials would force any opponent to surrender on the spot.
And the world-ending display Tierra produced on arrival was every bit as terrifying as Darkness's.
And yet...
Hikaru Amagi. The feeling that duelist gave off was nothing like that.
He seemed somewhat unhinged, yes, but as a fellow duelist, Declan could sense the burning passion and conviction in Hikaru's heart. He didn't seem like someone who would destroy everything.
Perhaps this goddess beside him, "Sophia," was the real god of destruction, framing Tierra on purpose. But that didn't seem right either. Tierra genuinely felt "malevolent" to him.
His expression remained unreadable. He calmly adjusted his glasses, countless thoughts racing through his mind while his face betrayed nothing.
Whether or not Sophia was deceiving him didn't change the fact that she had substantially elevated their world's strength.
He didn't trust Sophia, which was why he had refrained from establishing a "Ritual School." Synchro, Fusion, and Xyz schools had all been built, but the Ritual school remained on hold under the excuse that the timing wasn't right. A small precaution. He couldn't help it. His own father had burned him before. He simply couldn't bring himself to trust a foreign goddess.
Still, over the past few months, Sophia's assistance had been tangible.
So, after a final moment of deliberation, he spoke: "You're right. Since our world has gained a new power, we should take the initiative.
As I planned before, we go to the Synchro Dimension to seek allies. And while we're at it, we can participate in that grand dueling tournament. To provide more energy... for your awakening."
The red-haired shrine maiden kept her eyes closed, offered no response, and her figure gradually faded.
Clearly, she approved of this decision.
Declan looked at his left hand.
"Pendulum, huh..."