Chapter Forty-One: Working with Tsunade

"It's rare for you to come to me on your own. Is there something you need my help with?" Tsunade spoke as she poured herself a glass of sake, downing it in one gulp. After a full day at the Konoha Hospital, it was a luxury to be able to relax in the evening.

After finishing her drink, Tsunade asked again, "Is someone causing you trouble?"

"No, nothing like that. There is something I'd like to ask of you, though. Of everyone I know, your medical ninjutsu is the best."

With that, Karn took several detailed case files from his backpack, each outlining terminal illnesses and their medical histories, and handed them to Tsunade.

"Is it possible to develop a special medicine to cure these diseases?"

Tsunade said nothing, simply took the files Karn offered and began reading through them carefully.

Nearly half an hour passed before Tsunade finally rubbed her brow, closing her eyes to collect her thoughts. She had worked all day, barely rested after her shift, and had now spent another thirty minutes poring over documents.

"Curing these isn’t difficult, but developing a curative medicine... I can’t guarantee it. It’ll need to be tested. However, the first two diseases shouldn’t be too hard. I remember my great-uncle did some research in this area. I’ll need to look up some references."

"The Second Hokage researched medical ninjutsu too...?"

Karn was a little surprised. He hadn’t expected the Second Hokage to have studied things like cancer or hypertension; it was unexpected.

"Not medical ninjutsu, per se, but it was related to similar conditions to what you’ve brought me..." Tsunade didn’t want to dwell on this topic, so she changed the subject. "But I’m currently developing a new medical jutsu, so this might have to be postponed for a while."

"Is it because of your brother?"

Karn’s question lingered in the air. Over the past year, word had slowly spread through Konoha—people were talking about how Tsunade, one of the Legendary Sannin, had a younger brother who couldn't become a ninja. This was the most frequent rumor brought back by Nonoyu, the medicine woman.

"Even someone like you, who’s rarely in Konoha, has heard about it, huh?"

Tsunade’s mood soured at the mention. She poured herself another few drinks. The more her brother Nawaki moped at home, the more she wanted to develop regenerative medical ninjutsu quickly. Not even their grandmother Mito could cheer Nawaki up; the blow of not being able to become a ninja was simply too great for him.

"The second thing I want to discuss is, in fact, related to Nawaki’s inability to become a ninja... Why don’t you stop drinking for now? Otherwise, you won’t be able to read the documents."

At Karn’s words, Tsunade reluctantly put down her cup, feeling she could easily handle much more alcohol, but since the next matter concerned Nawaki, she decided to listen carefully.

"Take a look at this. My team has been working on a project that, if successful, could help a person regenerate—even lost limbs could be restored..."

As he spoke, Karn handed Tsunade a dossier on the Desolation Virus. With her knowledge of human anatomy and organ systems, she would be able to understand it easily.

"This is..."

Tsunade quickly became absorbed in the material. The files covered the development and theoretical framework of the Desolation Virus, and Karn had even explained technical terms in a way that was easy to understand, in case she wasn’t familiar with certain algorithms.

There were also experimental records—this was the part Tsunade valued most.

This time, Tsunade was thoroughly engrossed. Two hours passed as she read, and by then, most of the other customers in the tavern had already left, leaving only their private room still open. But since this was Karn’s establishment, it didn’t matter.

"Animal trials have already been conducted, so the next step is human experimentation, isn’t it?"

Tsunade silently pondered this as she reached the end. She wasn’t sure how to feel about human experiments; after all, her great-uncle had conducted more human experiments than anyone. If it were up to her... While she felt some resistance, the thought of Nawaki made her realize she could overcome her qualms.

"It’s an extraordinary experiment. As it stands, it surpasses any medical ninjutsu I’ve mastered and, in some ways, even resembles the regenerative techniques I’m researching..."

Having finished reading, Tsunade gave the Desolation Virus very high praise. Her brown eyes gleamed as she fixed them on Karn.

"You want to collaborate, don’t you? To work together on perfecting the Desolation Virus..."

"That’s right, that’s exactly my intention. Its effects go beyond healing—the virus can also enhance human abilities to their limits. Perfecting the Desolation Virus would be a tremendous benefit to me as well."

Karn made no attempt to hide his ambitions. He wanted to research the Desolation Virus, and since this also offered hope for Nawaki, Tsunade—who was willing to postpone her reforms for Nawaki’s sake—could hardly refuse.

If the Desolation Virus could be fully understood, Nawaki could not only become a ninja again, but he might even be stronger than before.

According to the experimental data Karn provided, the main difficulty of the Desolation Virus lay in the subject’s self-regulation. Whether plants or animals, none could match a human’s capacity for self-adjustment. If humans proved lacking as well, they’d need to find ways to boost metabolism and prevent bioelectric overload...

Tsunade soon found herself considering experiments with the Desolation Virus. It was a coincidence—she had just been thinking of her great-uncle’s human experiments. After reading about the virus, the first thing that came to mind was her grandfather’s cells.

Her great-uncle had conducted extensive research on their grandfather’s cells, leaving behind a trove of related data kept at the Senju compound. Tsunade had reviewed these once before, but hadn’t thought much of it at the time.

Now, recalling it, she realized her grandfather’s cells might compensate for the risks of the Desolation Virus in experiments. Their invasive nature could increase viral fusion and enhance both metabolism and organ functions.

Was this just a coincidence?

Tsunade bit her thumb, frowning slightly as she thought. Her brother’s chance at recovery was right in front of her; just a few more experiments might suffice. But to use her grandfather’s cells in research... Should she ask Grandma Mito first?

"Tsunade!"

Karn’s voice snapped her out of her thoughts. "Well? What do you think? Will you work with me?"

"I have to go back and ask before I can give you an answer, but I think Grandma Mito will agree..."

Tsunade pinched the bridge of her nose. After a day of paperwork, more reading at night, and a bit of alcohol, she was feeling rather dizzy.

"If that’s the case, then I’ll await your good news, Tsunade."

Karn could tell that Tsunade was interested—she just had a few reservations. But if Uzumaki Mito agreed, those doubts would vanish in an instant.

"Are you leaving already? Well, it is late... Too bad I haven’t eaten yet..."

Tsunade stood up a bit unsteadily, but as she reached the door, she saw Karn holding a food box. He said to her, "There’s some packed food and sake in here—you can take it home and eat at your leisure. Kushina took home a big cake today too, so I’m sure she’ll save you some. That’s all for now. I’ll be heading off."

With that, Karn left.

Tsunade stepped out of the tavern with the food box. The cold night air cleared her head a little.

Hearing the clink of bottles inside the box, Tsunade pursed her lips and thought, "That guy... he really does know how to take care of people..."