After saying goodbye to Namikaze Minato, Li Yu returned home and reviewed his last two battles.
Li Yu realized that he had only ever specifically studied Wood Release and Medical Ninjutsu. He hadn't learned any other types of ninjutsu at all.
He couldn't keep using large-scale techniques like Deep Forest Emergence, Advent of a World of Flowering Trees, and the Wood Dragon Technique.
In a one-on-one fight, using those techniques felt like firing a cannon at a mosquito.
At least for now, his age and physical limitations meant his chakra reserves were limited.
He could only release the right technique at the right time to counter an attack and maintain his stamina in battle.
Li Yu immediately went to the clan's secret archive and found the Earth Release and Water Release scrolls. The Senju Clan had ninjutsu of both types. The First had naturally mastered Water Release and Earth Release alongside Wood Release, and Second Hokage Senju Tobirama was especially skilled in Water Release.
The scrolls contained quite a few high-level techniques.
"What are these scrolls?"
The words "Summoning Technique" were written on both scrolls.
Li Yu jumped up in delight. The Senju Clan's Summoning Technique must be for Shikkotsu Forest.
He eagerly opened one of them. It described the Senju Clan's Summoning Technique and provided an introduction.
"So many Summoning Techniques, and summoning formulas, too."
He found the Fivefold Rashomon used by the First. It could withstand a Tailed Beast Bomb from Susanoo head-on and deflect it, earning it a reputation as the strongest defense in the Naruto series.
It was an item-summoning technique that required the summoner to use blood to perform the Hand Seals: Boar–Dog–Rooster–Monkey–Ram. This summoned Rashomon. The gates themselves couldn't move, and vanished after completing their defensive role.
You could also summon Triple Rashomon, like Orochimaru.
The number of gates summoned could be adjusted to the needs of the situation, using more or less chakra to fend off attacks.
He also found instructions on how to summon Katsuyu. Then he opened the other large scroll and, as instructed, signed Senju Nawaki's name and pressed down his bloody handprint. He saw many other Senju Clan members' names on it, too, including familiar ones like Senju Hashirama and Tsunade.
"The Senju Clan has a deep connection with Shikkotsu Forest."
"Does that mean Senju Hashirama learned Senjutsu in Shikkotsu Forest?"
"If so, I'll go to Shikkotsu Forest and learn Senjutsu first. I can have Wood Clones learn the other techniques later."
With that, Li Yu bit his finger and shouted,
"Reverse Summoning Technique!"
The scenery shifted, and he found himself in a lush forest, the air thick with dampness and mist.
Just then, a fist-sized slug crawled out of the grass and came to rest at Li Yu's feet. It spoke.
"Lady Katsuyu knows you've arrived. I'll show you the way."
With that, it crawled inside Li Yu's clothes and up onto his shoulder, then led him to Katsuyu's main body.
When he arrived before the enormous slug, as big as a mountain, Li Yu realized that Katsuyu was far larger than she appeared in the Naruto series. The Katsuyu Tsunade summoned was only a part of her main body.
"Child, you're from the Senju Clan, aren't you? What brings you here?"
"Lady Katsuyu, I came to ask you to teach me the Senjutsu of Shikkotsu Forest."
"Senjutsu isn't something just anyone can learn. Since you want to learn, I'll teach you. Whether you can master it is up to you."
The slug on his shoulder led him onward, to the edge of a lake shrouded in even denser mist.
"Feel and absorb Natural Energy here. I'll attach myself to you, and when you're about to turn to stone, I'll stop you."
Li Yu had seen the original story, and to learn Senjutsu as quickly as possible, he planned to follow Naruto's approach.
He formed Hand Seals, several tendrils extended from his body, and ten Wood Clones appeared in an instant. He planned to train with all of them at once.
Seeing this, Katsuyu split into multiple slugs as well.
"You're quite clever. This might help you learn Senjutsu faster."
When Uzumaki Naruto trained in Senjutsu, Fukasaku couldn't keep up with him using just a stick, so he could only create three clones to train alongside him. Katsuyu, on the other hand, could split without limit, so there was no need to worry about that.
The eleven Li Yus sat cross-legged and began sensing Natural Energy.
Learning Senjutsu wasn't easy, but many hands made light work. Training in Senjutsu at Shikkotsu Forest even came with a numbers bonus.
He spent three days in Shikkotsu Forest and had more or less mastered Senjutsu.
Unlike the toads of Mount Myoboku, Senjutsu from Shikkotsu Forest made a ring of green markings appear on his forehead, with a green dot in the center, while green markings appeared around his eyes.
He looked exactly like Hashirama in Sage Mode.
"Ha ha! I've finally learned Senjutsu!"
"My jōnin chakra reserves aren't enough, so Senjutsu will make up for them."
Thanks to the Senju Clan's powerful bodies and the unique nature of the slugs in Shikkotsu Forest, he could create several clones to absorb Natural Energy.
When Naruto fought the Six Paths of Pain, his limit was activating Sage Mode three times in a row, for five minutes each time.
As a member of the Senju Clan, Li Yu could currently activate it four times in a row, for seven minutes each time.
"Ha ha! The Senju Clan has a strong constitution, and they've awakened Wood Release, so they're very attuned to Natural Energy."
His three-day leave passed while he trained in the Senjutsu of Shikkotsu Forest. It was time to put his mask back on and return to work in Anbu.
He continued patrolling the village each day, while two clones studied Water Release and Earth Release at home and, as a side project, looked into the Flying Thunder God technique.
The Senju Clan had quite a few valuable scrolls in storage. This only strengthened Li Yu's resolve to restore the Senju Clan.
He would train in the Rasengan using the method Naruto followed in the story and see if he could learn it. As an A-rank technique that required no hand seals, it would be a useful technique that could eventually become an S-rank one when combined with an elemental nature.