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.