Evening, Hospital Director's Office
"Kakashi, I heard that your Wood Style experiment was a success?"
Tsunade looked up from the documents she was reviewing and asked casually as she checked over the work of the three apprentices.
"Yes, Sister Tsunade. The first successful subject from the Wood Style experiment has already been picked up by the Third Hokage. He said he would personally take him as his disciple," Kakashi replied respectfully.
"Oh? The old man's calculations are quite precise," Tsunade said with a trace of disdain in her voice.
She still carried a deep grudge over the deaths of 32 Senju clansmen during the early Wood Style experiments. The Senju, once a prestigious clan, had already been devastated by previous ninja wars. Now, only a few elderly and frail members remained.
If it hadn't been for her apprentice's proposal of a safer experimental method, the Senju clan might have been wiped out entirely before even achieving one success.
"Kakashi, now that the Wood Style experiment has succeeded, you should return to the hospital and continue your internship," Tsunade said firmly.
No matter how strong one's theoretical knowledge was, real skill in medical ninjutsu could only come through hands-on experience.
"Well... Sister Tsunade, I've actually made an appointment with Lord Orochimaru to study research methods with him more systematically," Kakashi replied, scratching his head, looking slightly embarrassed.
"Hm? Don't forget whose disciple you are," Tsunade said sharply, turning her eyes on him.
"Of course not. You are my true master, Sister Tsunade!" Kakashi quickly clarified. "I just want to learn from Orochimaru-sama's work and apply it to medical research."
Having lived two lives, Kakashi had developed a strong sense of self-preservation.
"Hmph, that's more like it," Tsunade nodded, seeing that Kakashi still had his priorities in order. She didn't press the matter further.
Kakashi let out a silent sigh of relief. He had passed this test—barely.
After spending so much time together, his relationship with Tsunade had grown to resemble that of siblings. She was strict with him, not out of harshness, but because she feared he might be tempted down a dark path. Kakashi, in turn, hoped to earn her approval through his actions.
---
Later that Night
After classes ended, Kakashi and Rin headed to their usual spot to eat tricolor meatballs. Ever since their evening classes began, grabbing a late-night snack had become a small but cherished ritual for them.
As for Obito, after coming to understand the situation within the Uchiha clan—and undergoing more than two years of Kakashi's intense training—he had become far more driven. He now dedicated this time to his own training.
Kakashi and Rin, however, always brought back food for him.
"Hey, Rin," Kakashi said as they sat in the warmly lit Sansemeiwanzi shop. The nostalgic, cozy decor reminded him of a dessert shop from his previous life. "Have you made any progress on the Hundred Healings Mark that Sister Tsunade taught you?"
"Not yet," Rin mumbled, cheeks full as she clutched her dango skewer. "The technique is way too difficult. I think it'll take at least another six months."
It wasn't a matter of talent. For someone not even ten years old, learning the S-rank Hundred Healings Mark was already an incredible feat. It was just a matter of time and maturity.
"I see. If you have any questions, ask me anytime. I'll teach you step-by-step," Kakashi offered.
He mentally calculated the time.
Just in case, Rin needed to complete the Hundred Healings Mark and learn Mitotic Regeneration as soon as possible!
"Really?" Rin's face lit up with joy.
Kakashi learned things quickly. With his help, she was sure she could improve faster.
Seeing her eyes filled with anticipation, Kakashi smiled softly. "Don't get too excited. Eat slowly, or you'll choke," he said, handing her a drink.
"Mm-hmm," Rin nodded, cheeks turning a little red under his gaze.
Ever since they started studying medicine together, something between them had quietly shifted. Their bond had deepened.
Kakashi noticed this as well.
This was not the same Kakashi who coldly rejected Rin in the original timeline. When he had first arrived in this world—frightened and uncertain—it was Rin who had stepped into his heart, illuminating his darkness like a sunbeam.
As time passed, this kind, bright girl had become an irreplaceable part of his life.
In fact, he had taken the reckless step of becoming Tsunade's apprentice primarily to find a way to prevent Rin's tragic death.
Therefore, unlike in the original timeline, he didn't shy away from her feelings just because Obito liked her.
Love was a matter of mutual affection.
Just because someone loved another deeply didn't mean they had a greater claim over them.
Besides, in the original story, after gaining the ability to resurrect the dead, Obito never considered bringing Rin back.
Part of the reason was that, under Madara's manipulation, Obito—young and emotionally fragile—had grown disillusioned with a world full of death and war.
But on a deeper level, even if Rin had been resurrected, she would never have agreed with his twisted ideals or returned his feelings. Rin had liked Kakashi. She had sacrificed herself for Konoha.
That's why Obito wanted to create a dream world—a place where Rin liked him, where they could be together. He wanted to force everyone else into that false paradise, regardless of whether they agreed.
---
"Kakashi? Hellooo?"
Rin waved her hand in front of his dazed face.
"The shop owner packed everything up. Let's go find Obito!"
"Ah, right." Kakashi came back to his senses and stood up, heading with Rin to the training grounds.
---
Konoha Training Grounds
Under the night sky, a young boy in a sweat-soaked training outfit was performing inverted sit-ups while hanging upside-down from a tree branch—his feet stuck to the bark with Chakra.
"Obito!" Rin waved cheerfully.
Hearing her call, Obito landed smoothly in front of them.
"Here you go," Rin said, handing him a warm container. "These are the tricolor meatballs we brought you. Eat them while they're hot!"
"Thanks!" Obito grinned, wiping the sweat from his face. He sat cross-legged and eagerly opened the food.
"I'm digging in!"
Clasping his hands together in a little 'itadakimasu,' he chomped down happily on the meatballs.
"By the way, Obito," Kakashi began once Obito finished, "I asked you to use up your maximum chakra and compress the Great Fireball technique to half its original size. How's your training going?"
"Hehe, I nailed it! Watch this!"
Obito stood up excitedly and walked a few paces away.
"Fire Style: Great Fireball Technique!"
With a practiced series of hand signs, he took a deep breath—and then exhaled a massive fireball nearly as tall as a person, lighting up the entire training ground.
"Nice," Kakashi nodded. "Next step: compress it to a quarter of its original size."
"Huh? Seriously? It was already tough shrinking it by half!"
"Yes. According to my calculations, if you can compress it to a quarter, the high-temperature explosion will reach the level of a B-rank ninjutsu."
"Also," Kakashi added, "if you master this technique, you can apply the same principle to enhance Phoenix Fire Technique to B-level power—while consuming less chakra than a standard B-rank move."
"Whoa, really?" Obito's eyes sparkled with excitement.
Like Rin, Obito had grown used to trusting Kakashi's judgment. So far, his advice had never steered them wrong.
"Exactly. The strength of a jutsu isn't just about the type—it's also about the chakra behind it and how well it's controlled."
"Take the Uchiha elder I told you about—his Great Fire Annihilation technique can rival an S-rank jutsu in power!"
Fired up, Obito dashed off to keep training.
Kakashi, meanwhile, turned to Rin.
"Rin, your control over water-attribute chakra has already surpassed that of most Water Style users. Now, I'll teach you a defensive technique—Water Style: Water Barrier."
"Try mastering the technique first. Once you're comfortable, work on reshaping the barrier to cover four sides."
"Watch carefully: Yin → Si → Zi → Si → Yin. Water Style: Water Barrier!"
With a smooth flow of hand signs, a solid wall of water surged up in front of Kakashi, shielding them both.
"I'm mainly focused on mastering wind and lightning chakras right now. My Water Style control is just average. So this is something you'll need to explore and develop on your own."
"Got it! I'll master it for sure!" Rin clenched her fists with determination.
The water chakra control training Kakashi had designed had already helped her tremendously.
With Rin and Obito's training goals set, Kakashi returned to his own research—this time, on Lightning Style chakra form transformation.
As usual, the three of them trained late into the night.
For them, this intense training regimen had already become the norm.