After Entering the Wrong Room, I Became Mr. Feng's Wife - Chapter 14

Xue Xi is forced to fall in love at first sight with this dangerous man on their first meeting. With death being the only other option, she makes the first move:

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!

This is the story of a modern sailor who was accidentally reborn as a soldier of the Brazilian Expeditionary Force, and finally became the largest plutocratic family in Brazil by virtue of his foresight.

- Description from novelbuddy