Within a Hollow Heart - Chapter 83: Volume 2, : "Veil’s Edge"

A Japanese salary man was reincarnated in a different world with swords and magic. He reincarnated into the family of a powerful noble. One day when he became twelve years old, he was suddenly summoned by his father.

「 I do not mind whether it is a woman in the town or a maid in our house, learn about women.」

Having gained the permission of his father, he uses his power as a noble to have his way with women.

While the demons were rising, mankind was about to become extinct. Six temples rose and protected the last territory of mankind.

A young boy joins the temple as a knight to save his mother. During his journey full of miracles and tricks in the world where temples and demons are antagonistic to each other, will he be able to ascend to the strongest knight and inherit the sealed divine throne?

- Description from novelupdates

In all my life, I’ve only made two mistakes that I regret. The first was filling out my entrance exam application wrong, and the second was offending Zhong Yuan. If I had to use an idiom to describe the impact of my mistake, it would be simply, ‘Life is no better than death’. And if I had to use an idiom to describe Zhong Yuan’s offenses to me, it would be simply, ‘Too many crimes to record’. And yet, for as evil and wicked as he was, he attracted girls the way that flowers attracted bees and butterflies.

It happened that one day, for some reason, I taunted Zhong Yuan, “The King of Hell sent you to torture some more people, didn’t he?” Without a change in expression, he replied, “In order to torture fewer people, I decided to just choose one person to torture for the rest of my life.” I asked him, “What do you mean?” He smiled at me and answered, “If you don’t go to hell, who will?”

- Description from Novelupdates

A college student, accidentally reborn into the world of Naruto, becomes a member of Uchiha who is destined to be exterminated.

In this cruel ninja world, in the face of endless wars and exclusion from the village, what will Uchiha Qing do?

PS: Later in the book, the protagonist will develop a system of immortal cultivation. Cultivating Immortals in the Ninja World, have you seen it?

- Description from novelbuddy