Tensei Shite Inaka de Slowlife wo Okuritai - Chapter 35: Demon King and the Hero, Along With the Lost Shield

A modern university graduate, traversing the window between two worlds, steals a celestial cultivation opportunity that originally did not belong to him. And this celestial technique, quite unorthodox...My credibility should be assured. In order to be responsible to the readers, I must earnestly remind you: my book is easy to linger on in your thoughts, so proceed with caution.

Never had the Radcliffe family expected their son-in-law, a loser in their eyes, to be the hidden Dragon Lord who had lived for myriads of years...

Among the demons, the supreme ones are called “Great Saints.”

A young man leaves his mountain village and travels around the world. By unceasing efforts, he finally becomes a legend of the age.

- Description from Novelupdates

A river song, triggered a legend of the rivers and lakes.
Tian Zun’s life motto: “My sword is the truth.”
Shen Lang’s life motto: “To serve people with morality, those who are dissatisfied are dead.”

- Description from uukanshu (translated)