What was a soul?
Tobirama Senju had written something on the scroll that touched on the very essence of life.
Was it an immortal spiritual entity, capable of reincarnation and traveling between worlds?
Was it the source of selfhood and consciousness, unable to exist apart from the physical body?
Was it a product of brain function, dependent on electrical signals from the brain's neurons?
Tobirama Senju had found no answer. But while researching the Yamanaka Clan's secret techniques, he had discovered that souls could be controlled with yin release chakra.
By carefully wrapping a soul in yin release chakra, one could move and manipulate it—not just one's own soul, but other people's as well.
That was also why the Yamanaka Clan's secret techniques could send their souls into other people's bodies.
Members of the Yamanaka Clan could master this ability to manipulate souls with yin release chakra after only a little training.
Tobirama Senju had recorded the training methods for the Yamanaka Clan's secret techniques in detail on the scroll.
Empty the mind, extract yin release chakra, spread it evenly over the cerebral cortex, then slowly draw it inward.
The mass that could no longer be moved at the end... something that was both matter and consciousness, was the human soul.
Kawadera Uchiha thought, If I mess this up, won't I turn myself into an idiot?
Blah, blah... wouldn't that be the end of me?
Kawadera Uchiha had yin release chakra too. His chakra natures were fire, lightning, and yin.
Using genjutsu required yin release chakra.
Tobirama Senju had recorded his experiments. In total, he had extracted the intact brains of twenty Yamanaka Clan shinobi and kept them in nutrient solution.
With the right formula, the brains could survive, and their souls would continue to exist. They could even use