My Civil Servant Life Reborn in the Strange World - Chapter 232.

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

In the continent of Chang’an humans had lived as livestock and slaves to the Primordial Beasts. These beasts were ferocious, bloodthirsty and overwhelmingly powerful, but even so, the humans managed to prevail in the face of despair.

He became a teacher at the best magic academy in the empire.
….For being mistaken for someone else.

Zixu woke up to find himself in the world of *Naruto*.Too weak to survive? No problem—he has the Kaido template.Unfamiliar with the *Naruto* world and clueless about ninjutsu? No worries—devouring Sarutobi Hiruzen's soul will take care of that.Caught in the constant battles between ninja villages and struggling to protect himself? Simple—just start his own teaching faction.Lacking manpower? Short on talent? Easy—swing the hoe well, and no corner is too deep to dig.