Chapter Summaries

Karn asked Tsunade to develop medicines for several terminal illnesses and invited her to work with him on the extremis virus, which could help Nawaki recover. Tsunade became interested but decided to ask Mito Uzumaki for permission to use her grandfather's cells in the research.

• Karn gave Tsunade files on terminal illnesses, and she said she would need to run tests before promising to develop cures.
• Tsunade explained that her Medical Ninjutsu research had been driven by Nawaki's inability to become a ninja.
• Karn showed Tsunade the extremis virus research, and she praised its potential to regenerate missing limbs and restore Nawaki's abilities.
• Tsunade considered using her grandfather's cells to reduce the virus's risks and decided to consult Mito Uzumaki before agreeing to collaborate.
• Karn gave Tsunade a box of food and sake before leaving the izakaya.

Tsunade promised Nawaki she would help him become a ninja and defended Karn from Konoha's leaders, who wanted to investigate him and benefit from his serum research without funding it. After leaving the Hokage Building, Tsunade planned to discuss the research with Karn, while Karn asked Jiekang Weilai about Yakushi Nonō.

• Tsunade ate the cake Kushina had left for her, then pretended to sleep when Kushina found her eating the other slice.
• Tsunade promised Nawaki that she would find a way for him to become a ninja within a year.
• Tsunade told Hiruzen Sarutobi, Utatane Koharu, and Mitokado Homura about Karn's serum and refused to let them investigate or target him.
• Hiruzen Sarutobi refused to provide research funds but asked Tsunade to keep the village informed, and Tsunade left to discuss the project with Karn.
• Karn visited the pharmacy, waited for Jiekang Weilai to finish serving a customer, and asked him about Yakushi Nonō's studies.

Karn and Tsunade agreed to collaborate on experiments combining the extremis virus with Hashirama cells, while Hiruzen and Danzo prepared a scheme involving Kushina and Karn. The chapter ended as Karn stopped Kushina from approaching an unexpected visitor who had entered the closed Dessert Shop.

• Karn planned to have Yakushi Nonō study under Tsunade to keep her away from Danzo.
• Tsunade told Karn that the village leaders would not contribute to their research, so Karn offered to supply the equipment and death row prisoners himself.
• Karn and Tsunade agreed that she would find an Earth Release ninja and Hashirama cells for experiments combining them with the extremis virus.
• Hiruzen Sarutobi said he had deployed ANBU and sealed the border as part of a plan to strengthen Kushina's bond with Konoha and investigate Karn's medicines.
• Kushina visited Karn after her first day with her mission team, but Karn stopped her when an unexpected person entered the closed Dessert Shop.

Karn killed a Cloud Ninja spy who approached his Dessert Shop, then hid with Kushina while explosions drew Konoha’s forces to the scene. After they emerged and reported the attack, Karn questioned how Minato Namikaze had learned Kushina was in danger, making the gathered police suspicious of him.

• Karn recognized the dark-skinned man approaching his shop as a likely Cloud Ninja spy and shot him with submachine guns after Kushina appeared.
• The spy used the Substitution Technique, but Karn shot him again with a Thompson and an Assault Rifle, killing him.
• Karn hid with Kushina in a basement and set off grenades to draw Konoha’s ninja and deter any accomplices.
• Karn and Kushina emerged and told the Konoha Military Police Force that a ninja had attacked them, while Karn asked them to notify Tsunade.
• Minato Namikaze arrived and said an ANBU member had told him Kushina was in danger, prompting Karn and the police to grow suspicious.

After a Cloud Ninja spy attacked Karn and Kushina, Karn lost faith in Konoha and arranged to leave the village, while Tsunade investigated the incident. Tsunade learned that Minato Namikaze and an ANBU member might be connected and headed to confront Konoha’s leaders with Orochimaru.

• Karn told Tsunade that a Cloud Ninja spy had attacked him and Kushina, refused her offer of protection, and asked her to escort him out of Konoha.
• Tsunade persuaded the Security Force to let Karn leave, and Karn returned to the Marvel Universe after Tsunade and Kushina went out of sight.
• Kushina recounted the attack to Tsunade, including Karn’s question to Minato Namikaze and the ANBU member’s failure to protect them.
• Tsunade cursed the people behind the incident and promised Kushina that Karn would return to Konoha.
• Tsunade encountered Orochimaru on her way to the Hokage Building, agreed to let him join the research, and took him with her to confront the old man.

After Hiruzen Sarutobi’s scheme drove Karn out of Konoha, Tsunade worried that the extremis virus research and exclusive medicine deal would fall apart. Karn returned to the Marvel Universe and decided to seek a relationship with the Uchiha Clan while preparing to resume the project.

• Tsunade told Orochimaru that Karn had left Konoha after the confrontation, delaying the experiments and threatening Konoha’s exclusive medicine supply.
• Tsunade reassured Kushina that Karn would return, then asked Mito Uzumaki to warn those plotting against Kushina.
• Mito Uzumaki told Tsunade that she had little time left and urged her to protect Kushina and Nawaki without blaming herself if Nawaki could not be cured.
• Tsunade resolved to gain influence by completing medical reforms and taking control of the medical department.
• Back in the Marvel Universe, Karn reflected on Konoha’s attempt to test him and decided to contact the Uchiha Clan when he returned.
• Karn planned to obtain the extremis virus serum and research equipment after taking time to unwind.

Karn returned to Konoha, arranged to move the Extremis Virus laboratory outside the village, and told Tsunade he would limit his visits because he no longer felt safe there. He planned to expand his business through the Land of Waves toward the Land of Water, while Orochimaru warned that Sarutobi would not let Karn escape his grasp easily.

• Karn asked Tsunade to relocate the laboratory outside Konoha and restrict access, and she agreed to have Orochimaru build it.
• Karn arranged funding, equipment, and thirty death-row prisoners for the research, gave gifts and letters to his Konoha contacts, and told Tsunade he would rarely visit.
• Karn decided to expand his business beyond Konoha, using the Land of Waves as a base to enter the Land of Water and investigate possible recruits.
• Xia Chuan established a shipyard in the Land of Waves with hired shipwrights and carpenters, supported by Konoha chunin and samurai guards.
• Tsunade gave Orochimaru the plans for the new laboratory, and he remarked that Karn was wary of Konoha and warned that Sarutobi would keep pursuing him.

Karn negotiated a trade deal with Kirigakure, securing a future market for his medicines and other goods in exchange for collateral that included chakra metal. Meanwhile, Orochimaru and Tsunade continued testing the Extremis Virus with the First's cells and needed Karn to supply more serum.

• The Third Mizukage dismissed Karn's request to meet, so the Mizukage Assistant sent him to Genji instead.
• Genji agreed to trade medicines, grain, and ironware with Karn, protect his shipping fleet, and include chakra metal as collateral every two or three transactions.
• Karn and Genji set a port in the Land of Water as their trading site and scheduled their first transaction for two months later.
• Karn planned pharmaceutical and food-processing factories in the Land of Waves and a modern army and arms production in the Land of Tea.
• Orochimaru and Tsunade tested the Extremis Virus with the First's cells, but the experiment destroyed more equipment and used up their serum.
• Orochimaru told Tsunade to contact Karn for more serum so their experiments could continue.

Karn supplied Orochimaru and Tsunade with equipment and test subjects as they investigated whether the Extremis virus could stabilize Hashirama cells. Their latest experiment showed partial regeneration after an explosion, leaving them close to a possible success but still in need of further testing.

• Tsunade and Orochimaru explained that the Extremis virus suppressed Hashirama cells and improved healing, but subjects still exploded when their emotions peaked.
• Karn reviewed their data, arranged replacement equipment and serum, and discussed obtaining different kinds of subjects, including ninja.
• Karn continued managing supplies and subjects while practicing ninjutsu; his chakra developed all five elemental affinities, though Kakuzu doubted his combat potential.
• Karn paid Kakuzu to teach him the Earth Release: Hiding Like a Mole Technique so he could escape danger.
• A test subject's arm exploded but began regenerating, and Tsunade recorded the response as Orochimaru declared his hypothesis correct.

Tsunade, Orochimaru, and Karn reviewed a successful Extremis Virus experiment that gave the prisoner Tsuchiishi an instinctive ability to use Wood Release. Orochimaru killed Tsuchiishi and buried him, while Karn and Orochimaru agreed to continue testing before considering the serum for Nawaki.

• Tsunade praised Orochimaru after a test subject survived an explosion limited to his arm and asked him to test Tsuchiishi's ability to learn Wood Release.
• Tsunade left to report the results and request more serum from Karn, while Orochimaru planned to kill Tsuchiishi if he could use Wood Release.
• Karn arrived five days later and learned that Tsuchiishi had failed to master the Clone Technique but had quickly used Wood Release.
• Tsunade explained how the Extremis Virus and cells from the test subject and the First Hokage could help reproduce kekkei genkai, and Orochimaru strangled Tsuchiishi and buried him.
• Karn comforted the unsettled Tsunade with a promise of gifts, then reviewed the experimental procedures and asked Orochimaru to conduct more tests before they considered Nawaki's treatment.

After completing another batch of Extremis Virus experiments, Tsunade and Karn returned to Konoha, where Karn stayed at the Senju Clan Compound for safety. Kushina was delighted to see Karn and the gifts he had brought, and they sat down to dinner with Nawaki and Tsunade.

• Orochimaru used Karn's serum to begin thirty simultaneous Extremis Virus experiments, and Karn gave him another vial when Orochimaru asked to trade for one.
• Tsunade and Karn set out for Konoha so Tsunade could check on the Medical System Reform and bring Nawaki back if the experiments proved successful.
• As they neared Konoha, Karn explained to Tsunade why Kushina had grown close to him, and Tsunade invited him to stay at the Senju Clan Compound for safety.
• Karn agreed to stay at the compound because he feared further trouble from Konoha's leadership.
• Kushina returned from a D-Rank mission, found Karn and a pile of gifts, and quickly set aside her annoyance at his long absence.
• Karn served a lavish grilled meat dinner, and Kushina, Nawaki, Tsunade, and Karn gathered at the table.

Danzo tried to persuade Hiruzen to seize Karn and ask Tsunade about treating his injuries, but Hiruzen refused to act without more intelligence and only promised to speak with Tsunade. At the Senju Clan Compound, Tsunade told Nawaki that a treatment was being prepared for him, while Kushina later confided to Karn that she feared becoming a monster.

• Danzo brought pills reportedly sent from Kirigakure to Hiruzen and urged him to act against Karn.
• Hiruzen refused Danzo's proposal to seize Karn, citing the lack of intelligence and the danger of provoking him.
• Danzo asked Hiruzen to inquire about the research Tsunade had mentioned, hoping Karn's Extremis Virus Serum could repair his injuries, and Hiruzen agreed to speak with Tsunade.
• Tsunade told Nawaki that Orochimaru was helping prepare a treatment that could restore him, and she planned to take his cells.
• Karn returned to his guest room and planned to meet Nanami and recommend Yakushi Nonō to Tsunade.
• Kushina visited Karn late at night and asked what she should do if she turned into a monster.

Karn eased Kushina’s fear of becoming the Nine-Tails Jinchuriki by teasing her over an unpaid dessert bill, then gave her candy. The next day, Tsunade accepted Yakushi Nonō as a student, and Karn set out to visit the Uchiha Clan, leaving Tsunade outside the compound.

• Karn reminded Kushina of her unpaid desserts and calculated a debt of 763,700 ryo, then gave her lollipops and sent her to bed.
• Tsunade caught Kushina with the candy and took half of it.
• Kushina slipped away before dawn with her small orange wallet to train.
• Tsunade tested Yakushi Nonō, was impressed by her medical ninjutsu, and arranged for her to study at Konoha Hospital before taking her as a student.
• Tsunade refused to enter the Uchiha Clan Compound, so Karn continued toward the Military Police Force with the gifts on his own.

Karn, Tsunade, and Nawaki traveled to Orochimaru’s experimental base after his tests of the New Extremis Virus Serum succeeded. Karn and Nawaki received the serum, and they emerged transformed, with Karn discovering his strength had greatly increased.

• Karn told Tsunade that his meeting with Hamada Uchiha had been only a courtesy visit and that he had avoided raising business or cooperation.
• Tsunade brought Karn and Nawaki to Orochimaru’s base after learning that all remaining test subjects had adapted to the serum, and Karn checked the surveillance footage to verify the results.
• Orochimaru cultivated serum for Karn and Nawaki while Karn copied the research data and gathered Hashirama Cells.
• Tsunade tried to persuade Karn to join Konoha by offering protection and access to Wood Release techniques, but Karn refused unless Tsunade or Kushina became Hokage.
• Tsunade injected the serum into Karn and Nawaki, and after thirty minutes both completed their transformations.
• Karn shattered his metal restraints and realized that his strength, speed, and physical perception had improved significantly.

Karn and Tsunade tested Nawaki’s growing Wood Release and Extremis-enhanced abilities before the group returned to Konoha. When Root operatives tried to detain Karn, he vanished, leaving them to suspect space-time ninjutsu and report to Danzo.

• Nawaki used Wood Release to bind Tsunade, but she broke free and struck him for his carelessness.
• Tsunade and the others assessed Nawaki’s improved strength, chakra, and regeneration, while Karn considered how the Extremis Virus affected him and Nawaki.
• Tsunade, Nawaki, and Orochimaru prepared to return to Konoha after ANBU appeared nearby, and Karn gave Orochimaru the research facility and equipment.
• Karn asked Tsunade to deliver a duplicate IOU to Kushina and reminded her about the commission for terminal illness medicine.
• Two squads of Root operatives confronted Karn, but he vanished before they could take him in.
• The Root captain ruled out ordinary techniques, suspected space-time ninjutsu, and ordered the operatives to report to Danzo-sama.

Hiruzen learned that Nawaki had mastered Wood Release through the Extremis Virus Serum, but the serum was gone and Karn had refused Konoha’s offer. Tsunade and Orochimaru kept Nawaki out of missions for now, while Hiruzen planned to wait for Root’s return and Nawaki compared Tsunade’s colleague Dan Katō unfavorably with Karn.

• Hiruzen saw Nawaki use Wood Release and regretted not securing the serum’s experimental data, while Orochimaru said no serum remained and Karn had refused to join Konoha.
• Orochimaru agreed to keep Nawaki with him and let Tsunade train him in Wood Release, while Tsunade rejected Hiruzen’s suggestion that Nawaki team up with Kushina.
• Hiruzen ordered an ANBU operative to tell him immediately if Root shinobi returned and to send Danzo to see him.
• Tsunade stopped Nawaki from seeking missions and told him to train, as Orochimaru prepared to take A-rank or S-rank missions.
• Dan Katō greeted Tsunade and invited her out, but she declined and hurried home with Nawaki.
• Nawaki asked whether Dan Katō was Tsunade’s suitor and said Karn suited her better.

Karn considered how to build his power and businesses in both the shinobi and Marvel worlds, then brought new extremis virus research to the Biological Research Center. He presented Killian and Maya with a new serum production procedure as they argued over the stalled experiments.

• Karn weighed ways to protect himself from Danzo and Root, while the system showed that a search for another world might succeed within a month or two.
• Karn removed Hashirama cell material and human experimental data from his virus documents before heading to the Biological Research Center.
• Karn decided to establish a military security company to protect his growing businesses, employees, and friends.
• At the research center, Killian asked for more test subjects, while Maya argued that the researchers should recalculate their equations instead.
• Karn stopped their argument and handed them the new extremis virus serum production procedure.

Karn persuaded Maya, Killian, and the researchers to pursue a new direction for the Extremis Virus experiments, then managed his growing businesses and recruitment plans. After reviewing the pharmaceutical wholesale company, he learned that the Trading System had unlocked a search for a new trading world.

• Karn told Maya, Killian, and the other researchers that an experimental method had succeeded and urged them to investigate regenerative cells from organisms such as salamanders or geckos.
• Karn refused to reveal the test subject or data, then encouraged Maya and Killian to continue researching the Extremis Virus and prepare to reduce its potency and cost.
• Karn worried that Killian still wanted revenge on Tony Stark and considered recruiting trusted assistants whose loyalty he could secure with a Cursed Seal.
• Karn hired a headhunting agency to find highly paid assistants and planned to establish a Military Security Company before bringing the Extremis Virus to market.
• Karn reviewed the pharmaceutical wholesale trading company's finances and overseas operations, and stressed the need to protect its sales staff.
• The Trading System informed Karn that he could search for a new trading world again.

Karn prepared for a trip to the Harry Potter world, gathering gold, supplies, and two assistants before arriving in London. Unsure how to establish a trading connection, he hired a security company to find people named Granger and Dursley.

• Karn decided the new world was probably the Harry Potter world and packed firearms, gold, supplies, and technical documents for the trip.
• Karn bought tens of millions of dollars' worth of gold and hired Betty Ross and Laura Jones as assistants, assigning them research and business responsibilities.
• Karn received his gold, bringing his total holdings to three metric tons, and considered the risks and potential profits of trading for magical items.
• In London, Karn concluded he needed to find a wizard or bind a local person as a trading coordinate, and considered looking for Granger or the Dursleys.
• Karn hired Hasben's private security company to find Granger and the Dursley family, offering up to ten thousand pounds for both.

Karn hired Hasben to locate the Dursley and Granger families, then arranged a dental-equipment deal with the Grangers and bound the world trading coordinates to Mr. Granger. At dinner, he met Hermione, who had received a letter from Hogwarts and asked her parents about the school.

• Karn received Hasben’s information on the Dursley and Granger families and decided to approach the Grangers instead of the Dursleys.
• Karn paid Hasben to secure dental equipment, a warehouse, and a contract for the Granger clinic.
• Karn introduced himself to Mr. Granger as Kane Penter, sold the new equipment to the Grangers, and bound the world trading coordinates to Mr. Granger.
• Karn accepted the Grangers’ invitation to dinner and met Hermione Granger.
• Hermione showed her parents a Hogwarts letter and asked whether Hogwarts was a school that taught magic.