This time, steam continuously poured from Goliath's body in thick clouds that obscured his entire form.
The process was clearly much more difficult than the previous fusions.
Even Marcus and Usopp could see that something unusual was happening.
"Hey, hey, hey... is this actually safe?" Usopp asked nervously, backing up several steps as he watched Goliath's body temperature rise to the point where the air around him visibly distorted from the heat.
The scene was frightening. Steam continued pouring off Goliath in waves.
Marcus was equally concerned. He'd already started considering whether he should possess the sword to check its condition directly, even though that carried its own risks given what had happened last time.
Just as he was about to make that decision, the white and purple steam suddenly vanished completely, as if someone had flipped a switch.
"Hah... it's done."
Both Marcus and Usopp let out breaths.
"How is it?" Usopp asked curiously. After all, this was a sword capable of corroding minds and enslaving its wielders. Now that it had been reinforced with netherite, what would it become?
Goliath's chest hatch opened.
Marcus reached inside and withdrew the Shichiseiken.
Originally, the sword had been a brilliant emerald green, beautiful and alluring in an eerie sort of way. Now it was pitch black from tip to guard, like a blade that had been tempered in Armament Haki until the color had permanently seeped into the metal itself.
Wisps of ghostly energy quietly crept along the blade's surface.
Seeing this, Usopp immediately retreated to hide behind a distant tree. He vividly remembered what it had been like when Marcus had lost control to the sword.
But the sensation Marcus felt from the ghostly aura this time was completely different.
It wasn't corrosive or hostile. It was... deferential?
That surprised him.
Before, when he'd used Haki to forcibly suppress the curse, the ghost energy had radiated nothing but contempt and murderous intent. Even after being coated in his Haki against its will, it had continued to emit resentful, bitter feelings, like someone forced into submission but silently seething with hatred.
Now though? The energy felt obedient. Almost eager to please.
Like a once-proud queen who'd had the defiance beaten out of her and now existed in servitude.
He shook off the strange comparison.
He channeled Haki along his arm and into the blade. At the same time, the seven gems embedded in the blade began emitting a golden radiance.
Suddenly, purple ghost flames rippled along the entire length of the sword.
He gave it a swing.
A red line of ghostly fire carved itself across the ground, burning so hot that the sand and dirt fused into glass where the flames touched.
"Damn?!"
Marcus stared at the damage. He hadn't even tried to put strength into that swing. He'd just wanted to test the sword's response.
But it was as if the Shichiseiken had read his mind, releasing its power and exceeding even what he'd expected from a full-strength attack.
The sudden burst of frigid energy jolted Zoro awake from where he'd been napping. His eyes snapped open, immediately alert and scanning for threats.
When he saw it was Marcus, the tension eased slightly. But the moment he noticed the ghost flames on the Shichiseiken's, his entire body went back on high alert.
After all, Marcus losing control to that cursed sword was still fresh in everyone's memory. Seeing that ghostly fire made it hard not to think about that incident.
But then Marcus' hand brushed lightly along the sword's edge, gentle and calming.
Just like that, the Shichiseiken's menacing aura faded away.
Zoro was a swordsman, even if he specialized in katanas rather than straight blades. He could clearly tell that the Shichiseiken now was different from what it had been before.
The old sword had been violent and wild, filled with killing intent. The new sword still possessed that danger, but it was buried beneath a burning heat.
When he channeled Haki through it, the seven gems embedded in the blade shone with alternating red and white light.
"Good sword."
Zoro didn't know if he was imagining it, but he could have sworn the sword was communicating something like: "Even if you praise me, I won't change my loyalty."
"What the hell?"
He looked confused, wondering if he was hallucinating from being woken up so suddenly.
But he wasn't alone in that perception. Marcus had also "heard" something similar.
It was strange. Before, he could only sense crude emotions through the ghost energy, usually pure hostility, with occasional variations but nothing this complex or articulate.
Had the sword gained sentience?
If that was the case, then did all cursed blades eventually develop consciousness? They all had distinct personalities and preferences, after all. Maybe that's what defined a cursed blade in the first place.
The flames on the Shichiseiken's surface burned brighter, as if responding to Marcus' thoughts with something that felt like: "That's right! I am super smart now!"
"Shit... this really is an incredible transformation," he muttered, examining the blade more carefully.
The interaction between Minecraft items and regular objects from this world was producing results that exceeded his initial expectations.
His gaze shifted to Goliath, and a new idea began forming.
Goliath immediately felt cold sweat dripping down his back under that stare. He knew that look meant Marcus was about to ask him to do something crazy.
"Creator...?" he asked nervously.
"Goliath," Marcus said slowly, "if I asked you to swallow the Going Merry... could you recreate her perfectly?"
"Uh..." Goliath was briefly stunned by the question, then thought about it seriously before shaking his head. "Probably not. I don't have any shipbuilding knowledge or skill. It's not like material fusion where properties combine. If I swallowed the ship and recreated it, maybe it would just gain some special characteristics, similar to what happened with these weapons. But I couldn't rebuild her from scratch with all the proper shipwright techniques."
Marcus nodded, accepting the answer.
In the original story, the Going Merry had manifested a ship spirit, a klabautermann that appeared when the crew's bond with their vessel was strong enough. But after all his modifications and additions, he wasn't sure if that could still happen. The ship's structure and materials had been changed so fundamentally that it might no longer be unified enough to develop consciousness.
That's partly why he'd considered having Goliath swallow and recreate the entire vessel, to see if the fusion process would help rather than hinder any potential spirit manifestation.
But it was fine. The ship worked perfectly as it was, and there was no guarantee his experiment would improve things. Better not to risk it.
"Forget it."
"Hey! Marcus! You sure you're okay?" Usopp called from his hiding spot behind the tree.
Marcus simply waved in response, indicating everything was under control.
Usopp cautiously emerged and approached, still eyeing the sword warily. When nothing immediately tried to kill him, he relaxed and began examining the transformed Shichiseiken more closely.
"So this is what it looks like after the modification? I mean... it's not as pretty as before, honestly," he commented without really thinking about how the sword might react.
The original design had been stunning in its own way. When the ghostly aura had manifested, the whole weapon had possessed a strange, bewitching beauty that was simultaneously attractive and dangerous.
Now though? It was pitch black with occasional golden gleams from the embedded gems.
Not ugly exactly, but definitely less aesthetically pleasing.
If he had to make a comparison, the old Shichiseiken was like a tanned, curvy beach athlete in a bikini.
The new version, on the other hand, was like a busty nun in formal clothing, still attractive, but in a completely different way.
As if it had understood Usopp calling it less attractive, the Shichiseiken released a pulse of ghostly energy.
The temperature around him dropped suddenly, frost forming on the nearby grass. He shivered involuntarily.
Usopp looked a bit confused.
Marcus tapped the sword's hilt with one hand. The ghostly aura immediately retreated.
He could feel it even more clearly now, the Shichiseiken understood what they were saying.
If that was possible, then could Zoro's Sandai Kitetsu do the same thing?
Marcus' eyes shifted to Zoro, or more accurately, to the cursed blade hanging at his side.
Zoro noticed the stare and looked puzzled. He'd been napping earlier and had completely missed whatever experiment Marcus and Usopp had been running.
Now he was being examined like some kind of lab specimen, which was weird.
"Check this out." Marcus handed over Kashu, the sword he'd enhanced earlier. "Tell me what you think."
The moment Zoro's fingers wrapped around the handle, he could feel the difference.
In the One Piece world, sword grades went like this: Supreme Grade (12 blades) > Great Grade (21 blades) > Skillful Grade (50 blades) > Grade blades.
Kashu belonged to the Skillful Grade category, putting it in pretty elite company.
Sandai Kitetsu, on the other hand, was actually just a regular Grade sword, lower quality than both Kashu and Yubashiri.
The only reason Zoro had never replaced the Sandai Kitetsu was because of its cursed nature. That demonic aura boosted his combat power.
Between Yubashiri and Kashu, which was better? If you forced a comparison, Kashu was definitely superior in terms of raw quality.
But Zoro had never planned to replace Yubashiri anyway. That sword wasn't just a Skillful Grade blade, it represented a bond between men. He still remembered that old sword shop owner in Loguetown, handing over his precious blade with nothing but trust and hope.
That's why he'd kept it all this time.
But now...
Now he was actually considering it.
"This is Kashu? How did you improve its quality this much?" He examined the blade carefully. "Wait, don't tell me... is this what you did to the Shichiseiken too?"
Marcus grinned and pulled out the completely transformed Shichiseiken.
The cursed blade seemed to understand it was being shown off. Dark energy rippled along its surface.
"Pretty much. So here's my question, want me to do the same thing to Sandai Kitetsu and Yubashiri?"
Zoro was tempted.
"You can really do that for both of them?"
"Already told you I could. But fair warning, because of how my ability interacts with a blade's original properties, Sandai Kitetsu will probably get a massive power boost. But Yubashiri might actually get weaker. There's no guarantee this will improve every sword."
Zoro frowned.
Marcus explained the crafting mechanics, metal compatibility, and how his abilities layered with a sword's inherent traits. But judging by Zoro's blank expression, none of it was getting through.
"Forget it," he sighed. "Think of it like this: one sword is like a normal meal that fills you up. The other is like a meal that gives you a temporary power boost. My ability turns regular items into the second type, but not every item works that way. Some things just... don't mesh with some materials."
"Oh, now I get it." Zoro nodded seriously.
Marcus felt his eye twitch. Of course the food analogy was what finally clicked.
"So? Want me to enhance Sandai Kitetsu? Based on its cursed nature, it should be a perfect match for netherite. Might even push it up to Great Grade level."
Zoro didn't hesitate, he immediately drew Sandai Kitetsu and held it out. Then he unfastened Yubashiri as well.
But when his hand moved toward Wado Ichimonji, he stopped.
That sword didn't just belong to him. It symbolized his promise to Kuina, to grow stronger together with her blade until he became the World's Strongest Swordsman.
If he let Marcus modify Wado Ichimonji... would it still be Kuina's sword?
The thought alone made him pull his hand back.
"Something wrong?" Marcus looked surprised. Zoro wasn't usually hesitant about getting stronger.
"Nah, it's just... Wado Ichimonji is already a Great Grade blade. It's strong enough as it is. No need to mess with it."
"Fair enough." Marcus nodded. "Honestly, Wado Ichimonji might not be suited for this anyway. It hasn't shown any special attributes yet, and forcing a material change might do more harm than good."
Wado Ichimonji was one of the earliest Great Grade blades revealed in the series, which meant its design was simple. It didn't have the sinister aura of a cursed blade. Just a clean, elegant katana that seemed almost plain compared to more exotic weapons.
But appearances were deceiving. That "plain" blade had clashed with Mihawk's blade and survived without breaking. Looking at it closely, you could see it was anything but ordinary.
In the end, Wado Ichimonji remained untouched.
But Sandai Kitetsu and Yubashiri? They weren't so lucky.
Marcus called Goliath and had the iron golem consume both blades along with netherite ingots, initiating the fusion process.
Steam poured from Goliath's body as the furnace inside him worked overtime. When the process finally finished and his chest opened, Marcus reached inside and pulled out the newly forged Sandai Kitetsu.
Zoro took it, feeling the familiar weight but sensing something different about the weapon.
Before, Sandai Kitetsu's cursed nature had manifested mainly as uncontrollable sharpness, just a blade that wanted to cut everything it touched, whether its wielder intended to or not.
But now? The blade still had that aggressive edge. But the demonic aura felt... tamed somehow. And when he gripped the handle, the dark energy became almost gentle.
"It's definitely stronger now."
If he had to put it in terms anyone could understand: Sandai Kitetsu used to be like a wild kid causing chaos wherever it went. Now it was more like a rebellious teenager, still dangerous if left unchecked, but no longer completely uncontrolled.
The blade's appearance hadn't changed much at first glance. But when light hit it, the metal now reflected a faint golden sheen.
Yubashiri, though? That sword was a completely different story.
Originally, it had been a katana with a glossy black body and elegant wave patterns along the blade.
Now its entire form had shifted.
Both the blade and the handle had turned pitch black. A single golden line ran along the cutting edge.
If you had to compare it to a person again, Yubashiri used to be like a fashionable high school girl, energetic and eye-catching.
Now it had "gone dark," transforming into a mysterious woman with an icy aura that demanded respect.
The moment Zoro's fingers touched the handle, cold energy shot up his arm like he'd grabbed a block of ice.
He couldn't hide his shock. The change in Yubashiri was enormous, way bigger than what had happened to Kitetsu.
The Skillful Grade blade had probably jumped several tiers. It might even be approaching Supreme Grade level now.
And that completely black appearance gave off an aura similar to a blade infused with Armament Haki. It almost looked like a Black Blade.
Marcus was just as surprised as Zoro. He'd honestly expected Sandai Kitetsu to be the perfect match for netherite. But apparently Yubashiri had been the ideal candidate all along.