I've Become the King of Villains in the Game - Chapter 517 - 366: The Prototype of the Ultimate Move

All Ning Meng did was criticize the novel that she had read. When she woke up the next morning, she realized that she had entered the novel that she had read the previous night and became the unfaithful female supporting character. And soon, she would divorce her powerful husband and lead a miserable life. To prevent that from happening, Ning Meng has to find ways to stay by his side. That would mean she would make a lot of enemies along the way. Time for her to use the knowledge from the real world to turn her life around and not let others take advantage of her.

Follow Chen Ming as he accepts disciples, establishes a sect, and fights his way in a world that deems him a cannon fodder.
He goes against any common sense using his wits and novel knowhow to finish missions and arm himself against his cruel fate.

- Description from Novelupdates

When traveling back to Japan's late Muromachi Era, how to survive becomes a significant challenge!Now, Harano must live well under this high-difficulty challenge!

An otaku with a hobby of masturbating was reincarnated as the son of a great mage.

As soon as he was born in this life, he vowed with a goal of embracing women till his death.

That said, when he became 20 years old, the Demon Lord which was sealed by his ancestors revived, and now it is his role to seal it once again.

And that demon lord is sealed in a tower dungeon that is rumored to be impossible to capture.

However, by an unexpected coincidence, he had found out that the Demon Lord is also one of him, a kindred spirit from within,

so he joined her instead and filled several traps in the tower dungeon, and thus they enjoyed a s*x spree with all the women coming over!