[Oto no Kami, Otogakure's outskirts]
"What do you mean?", Danzo questionned, "Are you suggesting you were just strolling in Oto no Kami? Kakuzu, your reputation precedes you. Others might not know that, but I know you better than anyone"
"Oh?", Kakuzu titled his head, not believing a word
"You were tasked with assassinating Hashirama Senju, but failed miserably. This was a suicide mission, which you realized late. In revenge, you stole the Earth Grudge Fear technique from the first Takikage, and mastered it. But then you needed hearts, and took those of elders before fleeing. Now, I must say Takigakure is courageous. Sending someone who betrayed them in the past to their enemy. Do they want to be destroyed?"
Harumi hissed: "Takigakure underestimates us. First, their kage disappears, and now, they send a threat like this weird string guy on our lands? This would be enough justification to annex the land of waterfalls"
Kakuzu's eyes flashed with surprise, his knowledge surpassing his expectations: "You...You are the one who killed Tansen, aren't you?"
"What a bold accusation to make. I could deny it, but your beliefs matter little to me. To be fair, I must thank you", Danzo humed, "I was looking at kage-level materials, and your body certainly seem interesting"
"Again, I am not here to fight", Kakuzu spoke
"Yet, your thoughts and interests do not matter. You trespassed on my land, and I have a duty to eliminate foreign shinobi"
Kakuzu laughed: "Otokage, you and I are alike. If we collaborate, I could give you half of the lands of waterfall, without waging war. You would expand your territory without breaking the peace treaty. An interesting offer, is it not?"
Danzo contemplated the offer. More territory meant more resources, more people, more clients. A country's territory was often proportional to the hidden shinobi village's potential. This is why Konohagakure is so strong. Otogakure possessed a strong pool of talents, but ultimately, demographic made its growth inferior to that of the other hidden villages, in spite of Ether gas, chakra injection supplements and body refinement elixirs.
"If I needed territory, I could just march onto Takigakure right now, and take everything for myself. Fool, you just gave me justification to do so", Danzo spoke
"Yet, you still talk to me. Takigakure might be weak, but we still hold the Hero Water. The shinobi of our village would gladly sacrifice their lifespan for independance. This is why Takigakure possesses a tailed beast, and why nobody ever attacked us. Otogakure was the only one who attempted to do so, going so far as to wage an economic war with us. I must say your plans were diabolical, Otokage, and you pushed Takigakure to the brink of civil war. But this is why we must work together"
"Develop your ideas"
"Pressure Takigakure upon my return. I will say I failed to assassinate you, but survived. Under the threat of a war with Otogakure, they will naturally accept me as their kage. I will propose a peace treaty. Otogakure will provide us with rice, and glass products, and we will give you the territory you seek. Later on, Iwagakure and Kumogakure are likely to attack you. You will need an ally. Takigakure could be your shield in the west, so that you can focus on Kumogakure. All I ask in return is an alliance. A solid, bountiful alliance between-"
*SPLASH*
Hiramekarei was thrust through Kakuzu's heart. A strong gale of wind rotated the blade further, creating a vortex bomb inside of Kakuzu, who agonized.
"AAAAH", Kakuzu shouted, immediately retreating backwards
Four shadow masses escaped his body, two of which held broken masks.
"Bastard...", you tricked me
"A trick?", Danzo shook his head, "You are barely qualifying as a kage-level figure, and you talk to me as if we were equal. Tell me, Kakuzu, have you ever felt true fear? Boku, Yukiko, make sure everyone record this battle in their mind. Tonight, we march onto Takigakure"
Kakuzu could not believe his eyes. He was not being underestimated. He could feel it in his strings. The man in front of him was a monster. He held no openings. Stamina, Vitality, Strength, Agility, Weaponry, Ninjutsu, Genjutsu, Fuinjutsu, Chakra...Danzo had reached the realm of kage in all those attributes, developed his own ninjutsu and possessed the four-tails in his heart.
"I underestimated you...", Kakuzu muttered
"I must thank you, Kakuzu", Danzo spoke, "Without you, we would have needed to face irritated major hidden villages, and face, as you said, at best a pyrrhic victory. However, you possess knowledge of Takigakure. Its location, its resources, its forces. We will ally with the bloody waterfall, absorb them into our forces, and conquer the lands of waterfall. You were the key we never knew existed"
Kakuzu's eyes flickered. The three-tails stored into his own heart, became wild. It could sense the chakra of Matatabi and Son Goku, the tailed beasts. If Kakuzu died, Ibuze would die too, or be sealed again. Kakuzu's plight was an opportunity. Using Kakuzu's weakness, Ibuze took over.
Almost instantly, Kakuzu's remaining two shadow masses became glaringly red, reaching the level of kage in terms of chakra reserves. As for Kakuzu, he transformed into a red mass of chakra, bones forming onto his head and back, acting as a skeleton.
Danzo shook his head: "A beast...You think a beast can threaten us? That would be underestimating Otogakure"
Danzo did not summon the forces of Otogakure on a whim. Over the past years, the various Corps had gone through a fundamental strength. In the Shimura Operation, on the Iwagakure Western Front, most shinobi under his command were mere genins. Now, most of them had become chunins, jonins or even, for the most talented, elite jonins. The number of shinobi under his command, too, had increased ten-fold.
With the enhancement drugs, civilians became more talented than the average Shimura shinobi back when they were still in Konohagakure. But it was not all. The support corps, and kenjutsu corps, benefitted immensely from Danzo's own ninjutsu and kenjutsu research. The Otogakure Assassination Corps, the Sabotage Corps, the General Corps, the Genjutsu Corps...All of these factions composed of the village's elite complemented the six outer clans well.
It was not an army that Danzo had gathered. It was a formation of elite shinobi that far exceeded the common knowledge. A mere tailed beast, a three-tails, could be suppressed by Danzo alone. Even if he was not enough, he could have worked with Harumi to subdue it.
However, Danzo's mind was far more sinister. The Ether Gas was not sufficient to have immediate effects. So he had an idea. How to make it so that he could increase the concentration of chakra within the underground of Otogakure?
What if he captured a tailed beast that fully transformed, and tamed it like he had tamed Ibuze?
What if he made used the Ibuze, the three-tails' flesh and vaporized it to improve the Ether gas?
Then everyone would become similar to the silver and golden brother. Breathing would alleviate sicknesses and provide unbelievable chakra reserves to the most untalented civilian. In other words, Otogakure was not going to earn one more jinchuriki. It was going to earn thousands of semi-jinchuriki who held no tailed beast, but benefitted from the same benefits as hosting one.
For that, however, they needed Kakuzu to fully transform.