Demon Slayer : The Silent Journey - Chapter 1: Reincarnation

This is the story of Long Yi, who was killed because he took revenge for the girl he loved. Before he dies, a strange lightning carries his soul into a different realm. How will he live, when the first thing he noticed upon arrival is that, the man whose body he possessed is raping the country’s princess?

- Description from Novelupdates

“Heaven's Taboo Doggy Technique”Living his life as a cripple, Xuan never expected anything good in his life; however, the day he discovered a secret library in his sect, he was able to walk into a parallel world.A different world, a modern world of cultivators and his world.The library of taboo techniques awaits Xuan again: the milking technique, doggy technique, dual technique, or sword art technique—every technique in one library.He can now use every technique to boost his cultivation above the gods themselves. Goddesses want his immortal white juice, mothers want his body renew techniques, step-siblings want his meat raw. Xuan's body was the pinnacle of taboo in both worlds.The fucker of mothers, stripper of daughters, and the founder of all techniques—it was only a matter of time.

Humanity has endured for millions of years, but recorded history only spans a mere four thousand years. During that unrecorded deep-sea age, what exactly were we doing?Countless indescribable beings ruled the universe, and our powerful ancestors preserved the fire of human civilization under their threat.Then they disappeared, and we rose.Now, they are coming back, mysterious psychic powers are awakening, the flame of human civilization is slowly extinguishing, and no kings are in sight...Chen Ke opens his eyes to see a world full of ruins and himself on the brink of death.The moment his heart was pierced by the Blasphemous Dagger, he became a dying man without a heart.Able to survive only 2 hours...

Xiao Ze, who was dedicated to the people and vowed to become a generation of Ming Jun, accidentally fell on a little lady.
The little lady was born beautiful and lovable.
So Xiao Ze accepted his life and got the name of fear.

ps:
①The male protagonist has no concubine, and he is dedicated to serving the country.

- Description from novelbuddy