With the Daimyo's support, Tobi's proposal was immediately adopted. First, they spread word that the Twelve Guardian Ninja were being established, primarily targeting powerful ninja unaffiliated with any shinobi village, as well as certain powerful chakra practitioners within the country—such as the monks of the Fire Temple. They did not immediately press Konoha Ninja Village to send its people over. As Tobi put it, they should not be too eager, lest they provoke a backlash from Konoha Ninja Village.
Training samurai, however, did not require any consideration of Konoha Ninja Village's opinion. The Daimyo first assigned three hundred samurai from his own family to Tobi, making them the first group to receive enhancement through the secret medicine. Carefully cultivated by the Daimyo's family, these samurai were formidable fighters. Some could use chakra at a basic level. Although the others could not, they had trained their bodies to be strong and resilient and possessed exceptional taijutsu skills.
The essence of Tobi's secret medicine was the special power he infused into it. This was an ability he had acquired after awakening, just like his ability to absorb resentment to strengthen his chakra. Once it entered another person's body, it effectively planted a seed of his will within them. That seed could rapidly awaken their potential and allow them to master chakra. However, this method had severe side effects. Over time, the recipient would lose their sense of self and become Tobi's puppet, while their body gradually grew stiff and cold, like that of a dead person.
To give a more concrete example, someone implanted with a seed would eventually become something like the clay puppets produced by Impure World Reincarnation. Aside from their bodies still being alive and their inability to revive, they would be identical in their obedience to commands and