The Nine-Tails had always been one of Konoha's greatest military assets!
As one of the nine tailed beasts, the Nine-Tails was so powerful that even several tailed beasts combined were no match for it! Legend had it that only the Eight-Tails could face the Nine-Tails one-on-one, yet it had ultimately still been defeated by the Nine-Tails' inexhaustible chakra!
Therefore, after the First captured the nine tailed beasts and distributed the others among the various villages, he alone kept the Nine-Tails for his own village. Whether that had been the First's intention or the Second Hokage Senju Tobirama's, the Nine-Tails, the strongest of all tailed beasts, ultimately belonged to Konoha! At least, that was how most Konoha shinobi saw it.
Ever since obtaining the Nine-Tails, Konoha had never abandoned its efforts to achieve perfect control over it or conduct research on it, using its immense chakra to strengthen the village!
The young man named Sora before them was the miniature Nine-Tails that had attacked Konoha back then—or perhaps pseudo-Nine-Tails would have been more accurate. Examination had revealed that Sora's body contained a massive amount of pure Nine-Tails chakra, enough to allow him to undergo tailed beast transformation!
What happened back then had been the best proof!
At that time, Sora had directly sprouted five tails, and the sixth had flickered in and out of view. When Ueno Kei later learned of this, he became quite curious. If simply storing Nine-Tails chakra could enable tailed beast transformation, did that mean Konoha could artificially create large numbers of artificial Nine-Tails jinchuriki?
Even if those jinchuriki could not compare to the genuine Nine-Tails, their power was still beyond that of ordinary shinobi. Well, sanity was a serious issue, though. If they could not distinguish friend from foe, then the more such jinchuriki there were,