A modified version of the Living Corpse Reincarnation.
Although Orochimaru's research had yet to reach such a stage, Suguru created a branch of Orochimaru's research to suit his own needs. He knew of the cons of Living Corpse Reincarnation, so he theorized a different technique.
An improved derivative, if Suguru had the leisure to call it that.
Suguru already had an idea of the components he needed to complete his derivative technique and turn it into a worthy Kinjutsu, inspired greatly by the distant future's Yakushi Kabuto. Using the Hozuki clan's Hydrification Jutsu, the Iburi clan's Kekkei Genkai that turns them into smoke, and Sakon and Ukon's Kekkei Genkai which lets them control their bodies at a molecular level, he had quite the aspiration.
'I just need to get their cells somehow.'
His derivative technique would also benefit from the strong life force of an Uzumaki descendant and some Hashirama Cells.
The completion of his personal technique would thus take a long time. For now, Suguru could only lay the foundations:
An application of the Yamanaka clan's Mind Transfer Jutsu, Sakon and Ukon's Kekkei Genkai, and the Spirit Transformation Jutsu that Kato Dan was famous for.
'Luckily, everything can be found in the same place.'
Suguru still felt like laughing when he realized that everything he needed had copies in Orochimaru's various labs.
'If not for Orochimaru being such a hoarder of knowledge, I wouldn't have been able to even conceptualize my plans!'
Truly, Orochimaru's generosity was beyond words, especially given his meticulous nature. Suguru just found it weird that Orochimaru never seemed to use such jutsus despite having them in his possession. Was he really that big of a collector that many other jutsus would simply rot in his libraries?
'...I think he is indeed a guy like that.' Suguru thought.
Inevitably, Suguru just shrugged and left the explanation to Orochimaru's preferences. Although he had spent months watching the snake man's every experiment, Suguru still found Orochimaru's brain difficult to understand. Suguru had even copied down a lot of Orochimaru's notes, repeatedly amazed by every innovation that he came up with.
Orochimaru's quirky trips outside the village seemed an integral reason why he could advance his research. Meeting different clans and people and witnessing a variety of Kekkei Genkai wouldn't have been possible if Orochimaru had been permanently cooped up in his laboratories.
This reminded Suguru that he needed to go out too. His body was rotting inside his little apartment and he was slowly whittling down his parents' inheritance.
'Well, I do need to visit Orochimaru's labs. After all, I need a bit of Sakon and Ukon's cells or DNA and a copy of those elusive spiritual jutsus.' Suguru squinted as he swam in his thoughts.
All he had to do was visit at an appropriate time and bypass a bunch of seals.
"Easy enough!" Suguru grinned. "I think I have a good date in mind."
Those were some famous last words.
***
While waiting for that fated moment to arrive, there were two other events that Suguru had taken note of. One of which would be Might Duy's opening of the Eighth Gate to rescue Guy from Kirigakure's Seven Swordsmen.
The other event would be the completion of the Academy's rebuilding later this year. This meant that Uchiha Itachi would be enrolled, and his prodigal abilities would soon come to light.
These two events did not interest Suguru as much as he thought. Though it was a quiet way to confirm a few of his memories. From eavesdropping on Hiruzen's mission assignments and a little bit of spying on the shinobi approaching the Mission Assignment Desk, he formed a rough outline of current events.
Aside from the rapidly growing discontentment from the Uchiha clan and the sharply heightened suspicions of Konoha's higher-ups, Suguru felt that things were still going as per the original storyline. His presence only exacerbated a few existing plot points and did not create entirely new ones.
Frankly, Suguru felt bored. If not for the fact that he had a lot of research to study and spy on, he would've mingled with the main cast a lot more. He had chosen the life of a reclusive academic, with his face buried in books he could not see. He was too engrossed in borrowing Byakugans and Sharingans, familiarizing himself with their characteristics as much as he could.
He was an egg still waiting to hatch.
On that note, Suguru also continued to train despite seeing abysmal results. The insurmountable wall called talent was indeed an insurmountable wall in all its nuances.
Luckily, all that exercise helped him stay fit while serving as a good break from all the theoretical problems he usually dealt with. Though it was lamentable that he didn't have a lab of his own.
"Sigh," Suguru bit his lip, imagining the various scenes of success he so desired to achieve.
He had so many plausible theories just waiting to be tried, tested, and perfected. Nowadays, all he lacked were the appropriate skills and sufficient strength.
"Soon," Suguru breathed as an unrestrained desire began fermenting within his mind. "I'll be able to grow some wings soon. After that, I can then begin to learn how to fly."
Just like this, another year went by.
***
It was a chilly morning delivered by a fiercer winter than last year. It was an ungodly hour, given that the sun wouldn't rise until about three to four hours later.
This was the second year since Naruto's birth — and the day that Suguru finally found his chance.
"How poetic is it to find the most opportune moment on the first day of a new year? New year, new me!" Suguru chuckled at the thought. Then, with mirrored Byakugans in his eyes, he put his hands together to form three seals.
His chakra moved with each one he made.
[Dog » Boar » Ram]
'Transformation Jutsu,'
With a puff of white smoke, Suguru assumed the form of a small silver snake, paying homage to the sensei who didn't know he existed.
Suguru snuck out of his house, checked if Hiruzen was using his crystal ball every minute, and then made his way to one of Orochimaru's underground laboratories. He traveled a few kilometers and spent half an hour to ensure his safety and the confidentiality of his 'mission.'
He even felt as if he was being too cautious. Hiruzen had gone to bed several hours ago. The likelihood that he would randomly decide to look in his general location was almost zero. His instincts, however, begged to differ.
So, Suguru didn't bother taking any risks. His entire future rested on the success of this plan. Otherwise, he would have to take paths that were miles away when it came to desirability.
After steeling his resolve, Suguru slithered through the shadows, avoiding anyone who could sense him. He made sure to circle the residences of any shinobi while also skirting past any graveyard shift guards.
With his Kaisugan active, he had no blind spots. Moreover, if any insomniac Hyuga looked in his direction with an activated Byakugan, he could easily pull their gaze away with his [Resonance].
After another half an hour, Suguru arrived in front of a freshly repaired and renovated three-story building. The characters for "General Store" were written on a large signboard above his head.
'This is it,' Suguru flicked his forked tongue. 'Beneath this building is one of Orochimaru's favorite laboratories.'