Menma had an almost obsessive pursuit of researching the Kekkei Genkai of various Ninja Clans.
When he was in the Limited Tsukuyomi World, he also enjoyed collecting the Kekkei Genkai, studying their genes in an attempt to unravel the secrets of the Otsutsuki Clan.
As is widely known, every clan in the current Ninja World with unique abilities can trace their ancestry back to the Sage of Six Paths.
For instance, the famous Sharingan of the Uchiha Clan, the Byakugan of the Hyuga Clan, and the Shikotsumyaku of the Kaguya Clan… all these Kekkei Genkai are weakened versions of Kaguya's various abilities.
However, compared to Orochimaru and other mad scientists in the Ninja World who conducted inhumane live experiments, Menma maintained his moral boundaries even in the Limited Tsukuyomi World and refrained from performing live experiments.
On one hand, he couldn't accept the false reality of the Limited Tsukuyomi World. On the other hand, he didn't want to cross his own limits and descend into madness.
This internal struggle persisted until Menma launched the Fourth Great Ninja War against the whole Ninja World.
After looting Orochimaru and raiding several of his secret bases, Menma discovered experimental research data on the Iburi Clan in Orochimaru's lab notes.
This reminded Menma of the minor Ninja Clan that appeared in only three filler episodes of the anime before being annihilated.
The ability to transform into smoke was a Kekkei Genkai Menma had never encountered in the Limited Tsukuyomi World, sparking his desire to collect it.
Not in a malicious way… he simply wanted this clan to serve him by providing cell samples and blood for researching the Smoke Transformation Kekkei Genkai.
"Shura-sama, these are the historical records of our Ibuki clan. Everything is here." a stone chamber deep within the underground space, Gotta introduced his clan's treasured archives to Menma.
Although Gotta had verbally expressed disbelief that Orochimaru would betray their agreement, he tacitly accepted a temporary alliance with Menma while waiting for Orochimaru's arrival.
So when Menma proposed reviewing the Iburi Clan's history, Gotta didn't refuse and directly provided him access.
Seeing the sparse collection of historical scrolls in the stone chamber, Menma deduced that the Iburi Clan didn't place much importance on preserving their history and heritage, with most knowledge passed down orally.
Alternatively, the Iburi Clan's struggle for survival was so dire, with shortages of food, medicine, and daily necessities, that the importance of these historical scrolls had greatly diminished.
This was evident from the clan members' uniformly ragged clothing.
Even as the leader, Gotta didn't possess a decent weapon, resorting to using a hatchet during his fight with Kakashi.
In the dimly lit stone chamber, Menma ran his fingers over the dust-covered scrolls.
"I don't like owing anyone anything." Then Menma took out a scroll and threw it to Gotta behind him.
"This storage scroll contains enough food to feed a hundred people for a week."
Upon hearing it was food, Gotta caught the scroll with both hands and exclaimed gratefully, "Thank you."
Menma didn't respond, silently picking up a dust-laden scroll and immersing himself in the history of the Iburi Clan.
For Menma, this was just an emergency supply scroll he carried with him, filled with non-perishable food… nothing gourmet, purely for survival.
But for the Iburi Clan, who always rationed carefully, this food could sustain them for one or two months.
When Gotta returned to his clansmen with the scroll, he saw Kinoe engaged in combat with a silver-haired Ninja wearing a mask, while other clan members attempted to join the attack.
"Is this a pursuer from Konoha?" Gotta immediately transformed into a cloud of smoke and charged forward.
In the Kakashi's Anbu Arc, Gotta's Taijutsu combined with his Smoke Transformation allowed him to fight evenly with the Anbu Kakashi.
In the end, Kakashi only won by luring Gotta out of the cavern and into the forest, where strong winds scattered his smoke form, leading to his death.
But this time, when Gotta joined the battle in smoke form, he immediately used the Body Oxidation Technique, infiltrating Kakashi's body through his nostrils.
Kakashi, who had been fighting Kinoe with his family's swordsmanship, suddenly felt as though his internal organs were being scorched by smoke. Even his eyes flickered with traces of smoke.
"Ahhh-!" Kakashi screamed in agony, dropping his weapon and clutching his head, alternately clawing at his ears, lungs, and other body parts in pain.
"Wait!" Seeing this, Kinoe quickly formed hand signs and used [Wood Release: Wood Locking Wall], encasing Kakashi to force Gotta to release him.
"Why are you saving him?!" After emerging from Kakashi's body, Gotta reverted to his human form and demanded an answer from Kinoe.
"He is a Konoha's Ninja, he can't die yet." Seeing this, Kinoe quickly came up with an excuse: "Perhaps, I can interrogate him for intel on Konoha's pursuit squad... or even Orochimaru's whereabouts."
Using his Wood Release, Kinoe summoned several wooden tendrils to bind Kakashi tightly, making a show of preparing for interrogation.
Gotta frowned in thought, then nodded slowly: "Fine. I'll leave him to you. I need to report this to 'that person'."
Having said that, Gotta turned and left, handing the sealing scroll containing food to a woman in charge of the clan's provisions.
Once Gotta and the others were gone, Kinoe let out a quiet sigh of relief and approached Kakashi, who is still restrained by the wooden bindings, "I'm sorry, this is the only way I could keep you alive for now."
At this moment, Kakashi was still reeling from the searing pain of the smoke invasion, his body trembling, sweat dripping from his forehead as he looked up at Kinoe.
Kinoe had once been ordered to assassinate Hiruzen, only to be defeated by Kakashi. However, Kakashi, recognizing the value of a Wood Release user, had spared him and reported his existence to Hiruzen.
And now, Kinoe had returned the favor by saving Kakashi's life.
"Who are these people?" Kakashi asked while panting, "The 'that person' he mentioned just now… is he talking about Orochimaru?"
Though Kakashi had stumbled upon this underground hideout by chance, it was clear the Iburi Clan had deep ties to Orochimaru.
Kinoe shook his head, "Orochimaru hasn't arrived yet. It's 'Shura'."
"Shura seems interested in the Iburi Clan's Kekkei Genkai, so he's waiting here for Orochimaru."
"Shura..." Kakashi's Sharingan flickered slightly.
He remembered that lone, cold figure wearing the white three-eyed fox mask at the gates of Hyuga Clan's compound.
Though they had never fought, the fact that Shura had openly beaten the Hyuga Clan's top fighters and wreaked havoc in Kumogakure spoke volumes about his terrifying strength.
'And how had such a powerhouse even learned about Orochimaru's defection?'
"Tenzo!" Before Kakashi and Kinoe could exchange more information, Yukimi returned.
"Who is she?" Kakashi looked at the girl, who was about their age, before looking back at Kinoe in confusion.
"This is Yukimi. The only child left in the Iburi Clan. The others... were all taken by Orochimaru for experiments." Kinoe introduced her, his tone heavy.
Despite this being their first meeting, there was an inexplicable warmth between them, as if they were old friends reuniting.
"Taken by Orochimaru..." Kakashi didn't need to think hard to guess what had likely happened to those children.
Yukimi, unaware of the specifics, simply looked at the boy who reminded her so much of Tenzo with instinctive concern: "I'll help you two escape. If 'that person' comes looking, you'll both be in trouble."
Behind his mask, Kakashi's expression softened.
This kind-hearted girl, who is living in the depths of the earth yet still radiant with warmth, reminded him painfully of his lost companion.
Nohara Rin.