Philosopher’s Stone – Sabbaciel

With the final Shadow Rider defeated, the Key Holders could finally let their guards down a little.

Professor Crowler was especially proud this time. The card Hikaru drew to turn the Duel around, Scrap Fusion, was one Crowler had personally bought. For once, he truly felt involved. A rare and fulfilling moment.

What irked him, though, was that cowardly Banner had the nerve to say "Take care of the students" right before him.

'How insulting!'

The Slifer Red students, however, were visibly downcast. Jaden didn't speak or move much for days, surprisingly subdued. Having never experienced true parting before, seeing someone he cared for vanish into nothingness in front of his eyes for the first time, it hit him hard.

But this too was a kind of growth, perhaps his most important one. Even his HERO spirits could barely console him. Only Winged Kuriboh could bring the faintest smile to his face.

The only one seemingly unaffected was Atticus, who had once again participated in a Shadow Game and been immediately wiped out by Banner.

Still, this carefree guy just strummed his guitar and boasted that he'd now fought a true Duelist, so Zane needn't worry about him. He was fine! He could even use Red-Eyes Black Dragon freely now with the mask!

This differed from Hikaru's memory.

Originally, even after breaking free of the mask's control, Atticus could only use Red-Eyes again by donning the mask and enduring great pain to channel Darkness.

But not in this world. Here, Atticus could wear the mask at will and summon Red-Eyes as he pleased. Darkness's fragment had completely left the mask.

Three top-tier rare cards, gained for free, Atticus was honestly grateful to Banner. If only he hadn't been punched so hard during the Duel!

Now free of immediate crisis, Hikaru returned to daily life with the Fusion Club, spending time reading through the Emerald Book that Banner had left behind.

Truthfully, this Emerald Book should've been called The Book of Banner. Unlike in the original, where the Emerald Book symbolized universal truth and had to be found, this one had clearly been rewritten by Banner based on his personal knowledge and experience. The name remained only because he didn't bother changing it.

It contained vast amounts of knowledge personally compiled and tested by Banner, even detailing how to construct a Dimensional Gate using alchemy. It also listed numerous interdimensional coordinates, dazzling Hikaru with the possibilities.

It seemed that if he solved the book's alchemical puzzles, he could unlock and access new dimensions. If he learned how to construct gates himself, he wouldn't even need to rely on the academy's system anymore!

Inside the book was also the key to the "artificial dimension" Banner had once pulled them into. By mastering the book, Hikaru could freely access it, a huge advantage.

This was of immense value to Hikaru.

Just the alchemy workshop alone, filled with real, functioning tools left by Banner, was an inestimable treasure trove.

No matter how much Hikaru enhanced the tools he bought himself, they could never compare to Banner's originals.

Take that massive forge alone, half the size of a classroom. There was no way he'd ever get permission to install something like that at school!

"Your teacher left you quite a stash, didn't he?"

Tierra appeared in the workshop, inspecting everything closely.

She glanced at Hikaru's Deck. "I'd already suspected it. This dimension was artificially created by your teacher. It's an attached subspace to your school. Whenever the academy activated its Dimensional Gate, he could hijack it and drag you here."

"We lived through that already. No need to explain."

"I mean, this means your spirits could come, and live here through the book even outside of Duels." Tierra kept her gaze on his Deck. After a pause, she snapped her fingers. "Alright, you all come out."

At her command, the first to nervously emerge was Captain Crystal. Then came Golden Eyes Idol, Andal, and Fullmetalfoes Alkahest. The Flame Sword brothers only appeared after checking with Hikaru.

The space was large, but cramming so many spirits into it still felt tight.

Honestly, seeing so many spirits in one place gave Hikaru a surge of pride.

"Not bad at all," he mused. "You've always been stuck waiting inside your cards until I summon you. Now you can actually move around here and breathe a little."

These were his comrades, after all. Giving them space to roam and relax was the least he could do.

"This artificial dimension is vast. The stars floating in the sky might not be real, but they're still inhabitable." Tierra continued. "Oh, and hey, you there—the alchemist. Stop staring at the machine. If you want to try it, ask your owner."

"Ah!" Alkahest snapped to attention, startled, then looked eagerly at Hikaru.

So that was the idea.

Hikaru understood Tierra's meaning. If Alkahest could operate in this dimension, even crafting basic Normal Monster cards would be incredibly helpful.

The more card sources, the better.

He could even get help preparing other experiments ahead of time.

Hikaru nodded to Alkahest.

"Alright, enough chatter. Come on, human. Let's search for something."

"Search? For what?"

"The core. Or maybe... a card?" Tierra twirled her staff in the air, head tilted as she guessed. "Anyway, let's go."

She gleefully darted off, and Hikaru quickly chased after her.

He didn't know what had gotten into the "Chaos Origin Goddess", but what he knew was that he couldn't let Tierra do whatever she wanted unchecked, and that this was Banner's workshop; if she broke something, that would be disastrous.

Eventually, Tierra stopped in front of a control platform. Her hand trembled as she pointed, eyes gleaming with excitement.

"Here it is, human! Right here!"

Hikaru had never seen her so thrilled, not even when she first reawakened through Winda's body.

He approached and opened the compartment, eyes widening.

It was a card.

A green card.

It read: Sabatiel - The Philosopher's Stone.

As he read its effect, Hikaru felt his breath grow heavy.

[Pay half your Life Points. You may exchange this card's effect with any other card you own (even those not in your Deck) during a Duel. Then, immediately return this card to your hand. May only be used up to three times across all Duels.]

It was…

Pure power.

Absolute power.

"This..." Hikaru stared, swallowing repeatedly.

"Knew it!" Tierra clapped her fists together. "There's no way a human, no matter how gifted, could create a subdimension like this on their own."

"So, human?" Tierra's voice oozed temptation. "Do you want to touch this power?"

Hikaru gulped as he extended his hand…

But just before touching the card, he halted, exhaled, swallowed again, and opened his cracked lips to ask, "There's more to this, right?"

"Mmm~ Amagi Hikaru, you're interesting," Tierra replied, smiling cryptically. "Then let me explain more."

"This artificial dimension is far beyond what you expected."