Marvel: Trading with Worlds

"Husband, let's do it again... I love that strong feeling of being needed."

Kain shook his head and said, "No. Today, you need to study all the blueprints and operating principles of these weapons, complete your physical training, undergo blood tests, and go through serum body enhancement. You can't always indulge in things like this, Baby-5."

Having entered sage mode, Kain decisively rejected her. With his previous impulses completely drained, he had already planned out several tasks before even waking up. 

While he didn't mind coaxing Baby-5, her sense of need was just too overwhelming.

But Baby-5, with a longing expression, had already fallen in love with this feeling—being needed while also experiencing a newfound comfort. It was the first time in her life she had felt something like this, and to her, it was simply wonderful.

She wanted to bask in this blissful exhaustion, even if she barely had any strength left in her body. Clinging tightly to Kain, she wrapped both arms around his muscular frame, pressing her cheek against him.

"Then… just one last time this morning…"

Seeing this, Kain fought against the temptation, then firmly told her, "I need you to become stronger, Baby-5. The Kain Chamber of Commerce will need your protection in the future."

Hearing this, Baby-5's eyes turned red with emotion. She rested her cheek against his chest and said, "You need me? Then I'll start training right away! I'll protect my husband and the Kain Chamber of Commerce!"

Seeing how quickly she changed her mind, Kain let out a sigh of relief. Finding such an outstanding and obedient woman was a blessing—but it also made it incredibly hard to get out of bed.

In the end, Kain and Baby-5 made an agreement: for every new weapon she mastered with her Devil Fruit ability, she would earn a reward. The more difficult the weapon, the greater the reward.

The Buki Buki no Mi (Weapon-Weapon Fruit) had immense potential, and with Baby-5's obedience and stamina, she could theoretically even become as powerful as an Ancient Weapon like Pluton—so long as she fully understood its design and operating principles.

Right now, her strength was severely limited by her knowledge and perception. The most advanced weapon she could transform into was a missile, and even that lacked real destructive power. Most of the time, she resorted to becoming simple melee weapons, assisting Buffalo in battle.

What a waste!

Many Devil Fruits had extremely high potential, yet most people in the One Piece world failed to utilize them properly. Few users devoted themselves to fully developing their fruit's abilities, instead focusing on Haki.

And it made sense—Logia-type Devil Fruits were universally recognized as the strongest, and Haki was the only way to counter them. 

Most top fighters relied on Haki to overpower their enemies, with only a handful of Marine Admirals using their Devil Fruits as their main strength.

But when it came to the development of Baby-5's fruit, Kain had already formulated a detailed plan. There was no one in this world who knew more about weapons than he did—his knowledge encompassed hundreds of them.

Additionally, weapon-based Devil Fruit users were immune to the weapons they transformed into. If Baby-5 trained hard enough, she could theoretically transform into a nuclear bomb—creating the ultimate self-destruction technique.

If she pushed her abilities to their limits, her combat strength could easily rival pirates with bounties between 800 to 900 million berries. 

Of course, Kain would also help her compensate for her weaknesses, such as mobility and stamina regeneration.

Honestly, if he hadn't already obtained the Thunder Fruit, Kain would've seriously considered getting the Weapon-Weapon Fruit for himself. A user's strength was entirely dependent on the weapons they could create, making it an insanely convenient ability.

Right now, Kain was particularly interested in the Munch-Munch Fruit.

At this point, he didn't lack combat abilities—what he needed was more auxiliary support. The Munch-Munch Fruit was his top choice and the best available option. 

A significant limitation in his future scientific advancements stemmed from inadequate materials, restricting the realization of nearly 50% of his potential technological breakthroughs.

This was one of the reasons why Kain had his eyes on Wakanda. If he could acquire a substantial amount of vibranium, he might be able to overcome material constraints and produce a wide array of advanced technological products.

However, in the meantime, the Munch-Munch Fruit was a solid alternative. Even Wapol, after being expelled from Drum Kingdom, had managed to establish the Wapol Corporation using this ability to create a new type of alloy.

"Robin, any updates on Wapol?"

Kain strolled into Robin's office, leisurely sipping black tea. Most of his experiments were being recorded by Queen Red, allowing him to finally relax.

"I've already found his whereabouts," Robin replied. "But boss, I think you should reconsider taking action against a reigning king."

As she spoke, several hands sprouted from the desk, clearing away stacks of documents. Nico Robin, previously hidden behind the chamber of commerce's paperwork, was revealed. She was dressed in a well-fitted, elegant business suit, exuding an air of refinement.

"Don't worry," Kain waved dismissively. "No one will trace it back to me, and I don't intend to take his life. I'll just let the World Government deal with the headache afterward."

With his ninjutsu and magic, there were few in the One Piece world who could uncover his identity.

Robin sighed, pressing her fingers to her forehead. "Alright. Wapol is still in Drum Kingdom, and I've prepared a permanent pointer for you, boss. But in return, will you share any information with me?"

"I don't have much more to give. You drained me dry too quickly," Kain smirked. "But I can tell you this—there's a Poneglyph in the forest of Fish-Man Island. Even if you find the others, retrieving them won't be easy. For now, it's better to focus on strengthening the chamber of commerce first."

"Fish-Man Island? I see… but thank you, boss~"

A smile spread across Robin's face upon receiving this information. Using her Hana-Hana no Mi, she sprouted two hands on Kain's shoulders, straightening his collar and lightly patting his back.

"I'll have the permanent pointer delivered to you later. As for the other items you requested, there's been some news from Sabaody Archipelago. I'll have someone acquire them as soon as possible."

Robin was referring to rare resources unique to the One Piece world—exotic materials, rare races of slaves, Sea Kings-meat and delicacies, Treasure Tree Adam wood, and more.

Since he had arrived in this world, Kain intended to make full use of its unique resources.

Among other things, he had already stockpiled a large quantity of Sky Island shells, including Impact Dials. 

If combined with vibranium to craft armor, these shells could be used to absorb and store impact energy before releasing it in one concentrated burst.

The impact force of an Impact Dial was enough to level a building—something even the Green Titan would struggle to withstand. In the future, these shells would become the standard equipment for Umbrella's elite warriors.

Beyond Robin's efforts, the underground research labs within the chamber of commerce headquarters were also making significant progress.

Kain had no qualms about using captured pirates as test subjects. In addition to gathering human body data, he had begun transforming the strongest ones into G-Virus and Z-Virus warriors.

Unlike the Super Soldier Serum and T-Virus, these two virus strains didn't enhance human evolution. Instead, they were specifically designed to create biomechanical warriors, forcing continuous mutations and enhancements upon their hosts.

A common person could turn into a tyrant with strength exceeding ten tons after injection. These powerful pirates…

Unfortunately, the world of One Piece lacked the technology to create memory nano-alloys—otherwise, the enhancements would have been even more terrifying.

Among the captured pirates, fifty-three had bounties exceeding five million Berries. These were the most violent and disobedient ones. Kain transformed all of them into Z-Virus and G-Virus warriors.

Their bodies were reinforced with metallic bone armor, implanted with a Red Queen command chip, and equipped with advanced weaponry, including beam cannons and laser systems. Each was also fitted with a self-detonation device.

These fifty-three biomechanical warriors became the trump card of the Kain Chamber of Commerce in the One Pieceworld. Just twenty of them were capable of destroying an entire country. If all fifty-three were deployed, they could challenge anyone in the Donquixote Family—except for Doflamingo himself.

After all, Kain couldn't stay in the One Piece world indefinitely, and the chamber of commerce was still in its early stages. However, with the backing of two Shichibukai and his fifty-three biomechanical warriors, the organization's security was well assured.

Next on the agenda was the Door-Door Fruit.

Once Kain obtained the record pointer and intelligence on Wapol, he immediately used a flight spell to rush toward Drum Kingdom.

—

"Finally found it! I knew that move looked familiar. Sister Tsuru, take a look at this."

Gion smiled as she held a report left by the Marines, handing it to Vice Admiral Tsuru.

"That so-called 'Shichibukai Demon Mage'… I think that technique is actually a form of ninjutsu. We've encountered similar techniques in Wano, and we've gathered some intelligence on it."

As Tsuru skimmed through the report, a memory surfaced. She recalled the officer who had originally recorded this information—back then, he was her contemporary, but he had later served as a Vice Admiral in a New World branch before being killed by the Beast Pirates.

"Ninjutsu… that does make sense. But aside from that, Mage doesn't display any other traits of a ninja. Could he have learned Wano's training methods?" Tsuru mused.

Aside from the ninjutsu-like abilities, Mage's fighting style aligned almost perfectly with the powers of the Thunder-Thunder Fruit. Sengoku had already decided to do everything in his power to recruit him.

"I'm not sure," Gion admitted. "But Sister Tsuru, do you know why the World Government's attitude toward Mage suddenly changed? They were trying to win him over before, but now they seem more interested in spying on him."

Tsuru calmly sipped her tea before answering.

"Because of Doflamingo. His background is a bit... complicated. But honestly, this is just another foolish decision by the World Government. Sengoku isn't in favor of it. Gion, if you have time, you should go to Alabasta and subtly warn Mage. Let him know where the Marines stand on this."

"You want me to go?"

"Yes. There's no better choice. Smoker would be a terrible fit for this kind of mission—he'd just end up cursing out the World Government."

Tsuru chuckled.

She meant that Gion's approach should be discreet—just a hint, not an outright warning. It was rare to have a Shichibukaiwho wasn't an outright pirate. If the World Government pushed him too hard and forced him to turn against them, it would be a massive problem for the Marines.

Especially since he had eaten the strongest Logia—the Thunder-Thunder Fruit.

….

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