"Kakashi, you have grown up."
Hearing the familiar voice of the Fourth Hokage, years of suppressed emotions burst forth from Kakashi in a torrent of tears. "Sensei..."
Shishou watched the touching reunion of teacher and student, stepping back to give them space for their conversation. Using a phosphorus bug string in his hand, he continued to maintain the sealing barrier.
After a few more minutes, the sealing barrier began to falter. At the Fourth Hokage's request, Shishou and Kakashi brought him to the Hokage Rock. As they gazed at the thriving, peaceful village of Konoha below, Minato Namikaze, the Fourth Hokage, smiled warmly.
"Peace... it's so wonderful."
As soon as he finished speaking, the sealing barrier shattered, and the Fourth Hokage's soul dissipated into a wisp of shadow before vanishing completely.
Kakashi stood in silence for a long time before approaching Shishou. "If you ever need help in Konoha, you can come to me."
Although Shishou didn't know what the Fourth Hokage had discussed with Kakashi, this conveniently resolved the dilemma of how to explain his presence.
"We'll see," Shishou replied before using the Flying Thunder God technique to leave. He was exhausted and had no desire to linger.
As Shishou departed, Kakashi stared at the Fourth Hokage's carved face on the Hokage Rock, lost in thought. The Fourth Hokage hadn't revealed Shishou's identity to him, only asked him to assist Shishou if necessary.
Shishou returned to the Land of Demons' palace. Handing the activation talisman for the sealing room to the newly awakened Miko Miroku, he prepared to pull her back to bed.
"Oh no, I still have things to do. Don't cling to me," Miroku said, wriggling out of Shishou's grasp, straightening her attire, and leaving the room.
Annoyed at his missed opportunity, Shishou stretched lazily and then lay down on Miroku's bed, falling into a deep sleep.
In a half-awake state, he felt a figure sit beside his bed, back facing him. Shishou lifted the blanket and pulled the person into his arms before drifting off again.
The next morning.
Shishou was slightly surprised to see the person next to him.
"Miko-sama asked me to accompany you..." Uzumaki Eri's face turned crimson, filled with anxiety.
Shishou didn't say much, simply pulling the blanket back over them to sleep a bit more.
...
By noon, a refreshed Shishou appeared in his secret laboratory.
"Master, here are the devices needed for the experiment," his female assistant, clad in a lab coat, handed Shishou a list.
Glancing at the list, Shishou headed to the teleportation platform.
"Don't just stand there, come along. I'll get you some clothes and then we'll purchase the equipment and materials," he said to his assistant.
This underground secret base was built beneath Shishou's fertilizer factory, completely enclosed, with access solely via his Flying Thunder God technique. As a formality, he had constructed a teleportation platform.
"Yes, sir," the assistant replied, carefully stepping onto the platform beside Shishou.
After buying ten sets of clothes and some daily necessities for his assistant, Shishou began his quest to procure experimental equipment. By evening, using a combination of extra payments and subtle threats, he had acquired everything he needed.
Transporting the items back to the lab via the Flying Thunder God technique, Shishou felt utterly exhausted.
Returning to the Land of Demons, he spent some time with Uzumaki Eri, rejuvenating himself before heading back to the lab.
This morning, Shishou had discovered a special secret about himself while with Eri, finding newfound energy and vigor.
The enjoyment of this discovery was something he kept to himself.
Opening the three scrolls left by Orochimaru, Shishou began studying with the help of his assistant.
Once Shishou had grasped all the basic terminology, his assistant prepared the experimental materials, a task Shishou couldn't yet handle proficiently.
Three days later, Shishou had finally mastered the specific procedures, though not the cellular techniques themselves. Instead, he memorized all the steps involved in transplanting Hashirama cells using his exceptional memory.
Venturing into the forests of the Land of Fire, he harvested the abundant life force of the local wildlife before returning to the lab.
Sending his assistant back to her room, Shishou began preparing for his own experiment with Hashirama cells.
First, he brought out an important tool.
Uchiha Obito's severed leg!
Retrieving the limb from his storage space, Shishou extracted a White Zetsu from it, using his Sharingan to control it. He named it "White Zetsu Number One."
"Tsk tsk, only two left," Shishou noted, carefully storing Obito's leg back into the storage scroll before taking out a severed hand from the original White Zetsu.
Cutting off a small piece of the original White Zetsu's cellular tissue, Shishou began transplanting these cells into White Zetsu Number One using cellular transplantation techniques.
Perhaps due to their common origin, the transplant succeeded immediately.
This was to grant ordinary White Zetsu the same division capability as the original.
Shishou then channeled the energy absorbed by his phosphorus bugs into White Zetsu Number One.
Next, he manipulated White Zetsu Number One to begin asexual reproduction, or "mitosis."
Unsure whether the newly divided White Zetsu would remain loyal, Shishou controlled all ten of the freshly divided White Zetsu.
Taking out the Hashirama cell extract obtained from Orochimaru, Shishou began experimenting on White Zetsu Number One.
No way would he transplant Hashirama cells into himself. He didn't share Uchiha Madara's twisted "love" for Senju Hashirama!
Nor did he want Hashirama's face growing on his body.
That would make intimate moments with Tsunade rather awkward. Should he bow to "Grandpa" first, or wait until after?
Therefore, he planned to perfectly transplant Hashirama cells into White Zetsu and then use his phosphorus bugs to absorb and feed back the power, awakening Hashirama's strength.
The more Hashirama cells within White Zetsu, the fewer he would need to absorb, making it easier to succeed.
Without a perfect method, ordinary White Zetsu couldn't adapt to Hashirama cells, which was why Shishou sought Orochimaru's collaboration.
Aside from the original White Zetsu and Spiral Zetsu, created by Madara himself, ordinary White Zetsu didn't initially have Hashirama cells.
Otherwise, during the Fourth Great Ninja War, Tobi wouldn't have needed Yamato to strengthen the weak White Zetsu.
If all 100,000 White Zetsu had Hashirama cells, there would have been no need to capture tailed beasts. The 100,000 Wood Release White Zetsu could have easily conquered the ninja world.
The few White Zetsu that Orochimaru captured from Sasuke had Hashirama cells because they were clones of the original White Zetsu.
Before absorbing them, Shishou planned to manipulate White Zetsu to undergo "mitosis" and see if the newly divided ones also had Hashirama cells.
If successful, Shishou wouldn't need to transplant Hashirama cells into each White Zetsu individually.
After obtaining Hashirama's power, Shishou could proceed with his future plans.
Following Orochimaru's method, Shishou spent an entire day successfully transplanting the cells.
Instead of a partial transplant like Madara, Obito, or Danzo, he transformed most of White Zetsu Number One's cells into Hashirama cells.
Taking a deep breath, Shishou began manipulating White Zetsu Number One to undergo "mitosis."
"Whether this works or not, it all depends on this moment."