During her training, Uchiha Hikari naturally made use of her Sharingan—primarily for its dynamic vision and ability to replicate movement.
And, of course, the Shadow Clone Jutsu.
At first, Korin thought she was trying to cut corners with tricks like the Four Bodies Technique and was somewhat displeased. However, after Hikari earnestly explained the principles behind the Shadow Clone and how its dissolution returned experience to the original body, he said nothing more—though he quietly ramped up the difficulty of her training.
In the original storyline, Master Roshi took three years to obtain the Ultra Divine Water, while Goku managed it in three days.
This didn't mean their talents were hundreds of times apart.
Korin's combat power far surpassed theirs at the time, and with his Flight Technique, the duration of the challenge was entirely up to him. If he truly wanted to block them, they wouldn't have succeeded until their strength neared his own.
Uchiha Hikari didn't mind this.
She was already here—she might as well learn as much as possible.
Staying on the tower for so long posed a major problem: food.
On the first day, Korin casually tossed her a bag of Senzu Beans to stave off hunger.
But Hikari carefully stored those away and instead used two of the capsules she'd gotten from Bulma to set up a makeshift kitchen in a corner of the tower. She cooked meals every morning and evening, occasionally sharing portions with Korin.
The ingredients, of course, had been purchased in advance. The vacuum-sealed environment of the capsules prevented spoilage.
She also had a small, ten-square-meter capsule house for bathing and sleeping.
Finally...
At the end of the seventh week, Uchiha Hikari successfully seized the Ultra Divine Water.
And she sensed something different about her chakra.
It seemed...
To have mixed with something else—becoming more resilient and fluid?
"Though it's not quite what I expected, you should have mastered 'ki' by now," Korin remarked after dinner that evening.
"Really?"
Hearing this, Hikari wasn't entirely convinced. "So, can I use the Kamehameha or the Flight Technique now?"
Korin licked his paw. "I don't know much about the Kamehameha, but you can try the Flight Technique."
The principle behind the Flight Technique wasn't complicated.
Simply put, it worked like a helicopter—releasing one's ki beneath the feet to levitate, then adjusting its flow for movement. The challenge lay in ki control, somewhat similar to water-walking training in the Naruto world.
Hikari attempted it dozens of times.
Just as she began to doubt whether she could learn it, a strange sensation surged through her—and in the next moment, her body lifted slightly into the air.
"?!"
The instant her focus wavered, she plummeted back down.
But her eyes sparkled with excitement.
It actually worked?!
Korin, observing nearby, nodded. "Seems you've grasped the basics. Now, just remember that feeling and practice until it becomes second nature."
"Hmm..."
Hikari focused inward, then frowned slightly.
She was certain she'd used the principles of the Flight Technique—not something like Iwagakure's Ultra Light-Weight Rock Technique. Yet, this application of chakra shouldn't have been possible under the rules of the Naruto world—Minato had never heard of it either (the Ōtsutsuki clan aside).
So...
What exactly had her energy become?
Some mutated form of chakra? Or a hybrid of chakra and ki?
After a moment's thought, she shrugged it off.
It didn't matter.
However this energy had evolved, it was hers now. She just needed to master it.
"Well... I should probably take a break for a while."
Though Korin still had techniques she hadn't learned—
Like energy sensing and his telepathy (if it could even be taught)—
Hikari had been on the tower for too long. The intense training had left her physically fine (thanks to her regeneration) but mentally drained. She needed to rest before pushing herself too hard.
Before leaving, she tried asking Korin for a Flying Nimbus.
...No luck.
As a "weapon" with blood on her hands, she hardly qualified as "pure-hearted."
Instead, she settled for another large bag of Senzu Beans, gifted Korin her kitchenware and leftover fish supplies, and promised to return for more training someday before bidding him farewell.
---
During this time, quite a bit had happened in the chat group.
After returning from Pilaf's castle, Bulma recounted their adventures to the others.
Both Minato and Tanjirō were fascinated.
Minato, at least, had the Box of Ultimate Bliss in his world—a relic of the Sage of Six Paths that supposedly granted wishes (albeit in twisted ways).
But Tanjirō's Demon Slayer world had far fewer supernatural phenomena, making the Dragon Balls seem unbelievable.
[Iron Will]: Bulma, can the Dragon Balls really grant any wish? Even... bringing the dead back to life? Or turning monsters back into humans?
[Bulma]: Uh... probably?
[Bulma]: Do you have someone you want to revive, Tanjirō?
[Iron Will]: Yes... I want to turn Nezuko back into a human!
[Bulma]: ?
[Eternal Hero]: If I recall correctly, Hikari mentioned that Tanjirō's world has creatures called 'demons,' transformed from humans via blood transmission... So his sister must have been turned into one.
[Iron Will]: Right. That's why I joined the Demon Slayer Corps...
[Nameless]: If it's just about reverting your sister, you don't need the Dragon Balls. Your world already has doctors researching a cure—it shouldn't take long. By the way, have you met Lady Tamayo yet? If you want to revive others, only those who died within the past year can be brought back.