Nawaki's expression did not change in the slightest when he heard Sarutobi's doubts. He had long been prepared for this. With complete confidence, he said, "This is the latest subject we've been researching recently. Since we can drive a soul out of a clone, why can't we do the reverse and put a soul into a clone?"
Upon hearing this, Sarutobi immediately thought of something. One term slipped from his mouth: "Living Corpse Reincarnation!"
Kakashi and Yamato looked puzzled when they heard the term. Orochimaru, however, smiled. He had conceived of this jutsu, Living Corpse Reincarnation, back in his youth. His thoughts had been relatively simple then, so he had directly asked Sarutobi about it. Naturally, he had been severely rebuked and forbidden from researching it. Of course, Orochimaru had not given up. Now, he was finally on the verge of success.
"No wonder Orochimaru was so confident just now!" Sarutobi said with a complicated expression. "It seems this forbidden jutsu is about to succeed. But even if the previous clone was not a complete human, what about after a soul is added to it? Aren't you being cruel by tormenting it like this?"
"No, no, no!" Nawaki hurriedly shook his head. "Even after adding a soul, this test subject still cannot be called a human!"
"It has a body and a soul, the two basic elements of life. Why isn't it human?" Sarutobi asked with a frown, though his tone remained calm. He had not expected himself to discuss such a taboo subject with such composure, like an old scholar discussing an academic topic.
"Because the soul injected into the test subject doesn't come from a human!"
As Nawaki explained, he formed a hand seal with one hand and reached his right hand toward the forehead of the test