Time flies.
Tanjiro had been in the Dragon Ball world for nearly two months now.
Compared to when he first arrived, he seemed to have grown a bit taller. His reddish-brown hair had grown quite a bit longer, but the most striking change was the subtle shift in his entire demeanor—like he'd undergone a transformation, almost as if he'd been reborn.
When Uchiha Hikari arrived at the top of Karin Tower, Tanjiro was sitting cross-legged in a corner, deep in meditation.
Korin, the cat sage, was nearby, munching on dried fish.
"Oh? Miss Hikari, you're here?" Korin said.
"Hey, it's Hikari!" Tanjiro added.
"Master, Tanjiro," Hikari greeted them both with a smile, exchanging a few pleasantries before her gaze settled on Tanjiro's forehead. Her eyes narrowed slightly. "So, you've awakened the 'Demon Slayer Mark,' huh?"
Indeed.
The dark red scar on the left side of Tanjiro's forehead had transformed into a vivid, flame-like mark, unmistakable to the eye.
Tanjiro scratched his head, offering an explanation. "Well, after you asked me about the 'Demon Slayer Mark' last time, Miss Hikari, it wasn't long before I awakened it while trying to snatch the Ultra Divine Water. Master Korin already checked it out and confirmed there's no issue, so I didn't mention it to you or Bulma."
"Oh?" Hikari raised an eyebrow.
One of the conditions for awakening the Demon Slayer Mark was pushing the body to its limits through intense combat or training. According to Muichiro Tokito, the Mist Hashira in the original story, it required a body temperature of 39°C and a heart rate exceeding 200 beats per minute. For someone like Tan.Admin, who already had the potential, unlocking this ability after rigorous training wasn't surprising.
But…
Was she sure this wouldn't affect his lifespan?
After all, aside from Yoriichi Tsugikuni, who was born with the mark, no one who awakened it lived past 25. The Rock Hashira, Himejima Gyomei, was an exception, awakening his mark at 27 during the final battle, but even then, Muzan's words implied he didn't have long to live.
If not for this drawback, Yoriichi's brother, Kokushibo, wouldn't have turned to Muzan and become a demon.
"No need to worry," Korin said, finishing the last of his dried fish and licking his paw. "I've thoroughly checked Tanjiro. The reason the Demon Slayer Mark shortens lifespan is because it's an imperfect power. From the moment it's activated, it continuously drains the body's energy—like poking a hole in a water container. Over time, the water runs dry.
The solution is to use 'ki' to patch that hole and prevent the energy loss. I've figured out the method and taught it to Tanjiro. Whether he masters it is up to him."
"I see," Hikari nodded.
The training system in the Dragon Ball world was a step above the Breathing Techniques of the Demon Slayer world, and 'ki' was an incredibly versatile power. It made sense that it could counter the mark's downside.
On the other side, Korin glanced at Hikari. "You didn't come here just for that, did you? Got something else on your mind?"
"Two things, actually," Hikari said with a light cough and a playful smile. "First, it's about the Red Ribbon Army…"
"The Red Ribbon Army?" Korin pondered briefly before nodding. "I've seen glimpses of them in my water jug. By human standards, they're the most evil organization out there, responsible for all sorts of atrocities. People tremble just hearing their name. If you're planning to take them down, it'd be a good deed for ordinary folks."
"You think so too, Master?" Hikari asked.
In the original Dragon Ball story, Goku took down the Red Ribbon Army, and it didn't tarnish his reputation in Korin's eyes. But as someone from another world, Hikari hadn't been oppressed by them, so taking them out herself felt a bit like overstepping. Mentioning it to Korin was her way of getting a second opinion.
Of course, her efforts to build rapport with Korin over time helped make him more receptive.
As for the second matter…
"It's about the Dragon Balls," Hikari said carefully. "Master, what do you know about them? If… hypothetically, we wanted to borrow the Dragon Balls to use in another world, would that be possible?"
Korin's paw froze mid-lick, his squinting eyes widening slightly in surprise. "Another world?"
"Yeah," Hikari nodded. "I don't know if Tanjiro mentioned the Demon Slayer Corps, but many of its members have lost loved ones to demons—some even lost themselves. Tanjiro and I were wondering if we could use the Dragon Balls to bring them back. Is that feasible?"
Korin fell silent.
After a long pause, he spoke. "I can't give you a definitive answer. You'd need to ask the creator of the Dragon Balls."
"The creator?"
"Yup, the Kami of Earth," Korin said, stroking his whiskers. "Kami lives in the Heavenly Temple, far from the mortal world, and rarely meets humans. I can ask on your behalf. If Kami agrees to see you, I'll let you know."
"Thank you, Master!" Hikari said with a bright smile.
She'd thought through these issues days ago when she decided to collect the Dragon Balls again in this world.
First, gathering the Dragon Balls wasn't too difficult. The main competition was the Red Ribbon Army, and once they were dealt with, it'd be smooth sailing. Pilaf was also after them, but he was a comedic side character at best—more of a nuisance than a threat.
Second, taking the Dragon Balls to another world was just a matter of "crossing over."
The problem was…
Dragon Balls taken to another world likely wouldn't summon Shenron. Their power came from their creator, Kami. In the original timeline, when Kami died, the Dragon Balls lost their power. Taking them to another world might sever that connection, rendering wishes impossible.
Even if everything went perfectly, there was another issue: after a wish, the Dragon Balls turned to stone and scattered. If Hikari couldn't bring them back, it'd be hard to explain to the Dragon Ball world.
So, meeting Kami and laying things out clearly was the best approach. If Kami refused or the Earth Dragon Balls couldn't do it, they'd have to try their luck with Namek's Dragon Balls.
"Please pass on my request to meet Kami," Hikari said respectfully.
Since Korin didn't mention that the Heavenly Temple was right above Karin Tower, she played along and pretended not to know.
"As for Tanjiro…" Korin stroked his whiskers. "He's got talent and grit. He's close to snatching the Ultra Divine Water. If you need him for something, take him along. He can finish the final stage of training when you're back."
With that, Hikari handed Korin a prepared gift, said her goodbyes, and left with Tanjiro.
Tanjiro hadn't yet learned the Flying Nimbus technique due to his short training time, but he had Korin's golden Flying Nimbus, so he kept up with Hikari just fine.
Hikari was a bit jealous of the "authentic" Flying Nimbus but couldn't ride it herself, so she settled for admiring it.
"Wonder if Kikyo and the others could ride the Flying Nimbus?" she mused.
Kikyo, with her pure heart and "Light of Purification," would definitely qualify. Eri and Yoriko might too. Yamato, despite her quirky thinking, had a pure enough heart to likely make the cut. Brand and Yuji, though? Brand's hands were too bloody, and Yuji had Sukuna inside him—probably no go.
Chatting about "ki" with Tanjiro along the way, they soon reached West City's Capsule Corporation and met up with Bulma and the others.
Yamato, who'd been shopping with Bulla, rushed over excitedly when she saw Hikari, enveloping her in a… well, let's just say a very enthusiastic hug.
Literally, Hikari's face was buried in Yamato's chest.
Esdeath and Tanjiro, standing nearby, exchanged awkward glances.
"Alright, Yamato, let go—I can't breathe!" Hikari mumbled, pushing against the soft but firm pressure on her cheeks.
Once freed, she caught her breath and introduced Tanjiro.
"Oh, you're that 'Iron Head' from the group chat?" Yamato crouched down, poking Tanjiro's forehead curiously. "Is your head really that hard? Wanna try headbutting me?"
"Uh, I don't think that's a good idea, Miss Yamato…" Tanjiro hesitated.
"It's fine! It's just a headbutt, not like it'll hurt. Come on, let's do it!" Yamato insisted.
Reluctantly, Tanjiro agreed. They both took a deep breath, leaned back, and slammed their foreheads together.
Thud!
A sharp crack echoed. A small cut opened on Yamato's forehead, blood trickling down, while Tanjiro clutched his head but was otherwise unscathed.
Hikari and Bulma exchanged stunned looks.
"Wow," Bulma muttered.
"Even Yamato…" Hikari added.
If Tanjiro and Yamato fought, Yamato would win hands-down—her strength, inherited from Kaido, was overwhelming. But in a contest of forehead hardness? Tanjiro's "Iron Head" nickname proved itself.
Esdeath glanced at Tanjiro briefly but didn't pay him much mind—his strength wasn't enough to catch her attention.
That night, Bulma hosted a lavish feast for Hikari and the others. Afterward, Bulla arranged sleeping quarters.
Hikari found Dr. Brief and handed him some academic letters from Orochimaru, picking up his replies to pass back later.
Dr. Brief mentioned progress on the "Uchiha Bloodline Tracing Project."
"I've made some breakthroughs," he said. "From tests and comparisons, the Uchiha bloodline has a genetic flaw that affects brain structure, causing negative emotions to build up without release—what's called the 'Curse of Hatred.' As the Sharingan evolves, especially to the Mangekyo, this flaw worsens, intensifying the condition."
After explaining the science, he got to the point. "Based on these findings, I've developed a gene-targeting drug that can repair this flaw through injection. It also stabilizes the Uchiha's eye power without triggering the curse. I used genetic samples from Naruto and Karin Uzumaki, which also seem to work on that 'Kaguya Kimimaro' blood sample you provided."
He paused. "But these results are lab-based. We haven't tested on live subjects, so we don't know about rejection risks."
That made sense. Aside from Hikari, all Uchihas were in the Naruto world, so clinical trials weren't possible here.
"Please give me a few samples of the drug," Hikari said. "I'll find some clansmen to test it when I'm back."