"I'm no medical ninja, but I can try to deal with what's inside you."
After Ensei Uchiha had talked with Minato Namikaze and his wife for a while, Kushina Uzumaki asked him to help Minato with the problem inside his body.
As it happened, Ensei had been thinking along the same lines.
That old schemer Black Zetsu had hidden himself far too well. Even in the original story, he had revealed his true nature only at the very end, and he had never shown much of his actual strength.
He had hidden in the Shinobi World for a thousand years, claimed to have created the history of the shinobi, repeatedly incited the Sage of Six Paths' two sons to turn against each other, and guided Madara Uchiha into awakening the Rinnegan.
Those deeds were more than enough to prove how troublesome Black Zetsu was.
So Ensei had to kill him in one strike. He absolutely couldn't give Black Zetsu a chance to react.
A trace of caution showed in his eyes as Ensei activated Tenseigan Chakra Mode. Green Chakra enveloped his body, giving him a striking appearance.
"This is a power I've been developing. It's still unstable."
"So, Minato, stay calm and don't resist."
Ensei spoke slowly. Once Minato nodded solemnly, Ensei pressed his hand, glowing with green Chakra, against Minato's chest.
As Tenseigan Chakra flowed into him, Minato realized he'd lost control of his body. Fortunately, Ensei had warned him beforehand; otherwise, he would have instinctively resisted.
Tenseigan Chakra could partially seal a shinobi's own Chakra and control their body.
Hinata Hyuga had fallen victim to this several times in the original story.
After a few attempts, Ensei quickly mastered the technique and successfully took control of Minato.
Next, he began investigating the dark energy within Minato.
It was