Pastoral Daily Life - Chapter 81: (Rebirth)

Transmigrating into a poor and mistreated young lady's body, what will the craziest alchemist of the seven realms now do?

He is a young man without a spirit root. It is believed that this denies him the chance at cultivation. However, a mysterious lady imparts a Supreme Demon Classic to him and from then on, he starts his path of cultivation.
He undergoes a total transformation to emerge as the most fearsome and powerful fiendish demon in his era, that even immortals and fiends are fearful of him, and saints are at his beck and call.
Mastering the Supreme Demon Classic is the turning point in his life. He is able to unleash his immense and divine power from within, illuminating the entire universe!

- Description from Novelupdates

Master said, the woman I held in my hands, I must protect for the rest of my life.

In this story, a regular guy from our world becomes a young Main Branch heir of the powerful Hyuga clan in the Naruto world.He's primarily interested in gaining more power and doesn't care about right or wrong. He uses his knowledge from Earth and the Naruto show to get ahead, using his creativity and intellect to the utmost.As he tries to become more powerful, we see sides of the Hyuga clan and ninja world that weren't shown in the original Naruto story.He looks into the secrets of his ancestors, the Hyuga's eyes, and how ninja politics work, finding out things we never knew before and that the original author left unexplored.However, gradually, along the way, he also meets new lovers, friends, subordinates, and enemies and challenges how things are done in the ninja world - and also tries to unify it in the process and bring real peace around.