A Hentai System in the World of Danmachi - Chapter 54 - 53 - It works better on "NPCs".

A great demon king who came from another world to conquer Earth. To save the Earth, Li Luyou could only first take care of this great demon king… a little girl proclaiming herself Her Imperial Princess.

- Description from Novelupdates

On a dark and windy night, he picked up a beautiful, charming, sexy and enchanting beauty, and his life was filled with ups and downs...

At the end of a Dynasty filled with Demons and rampant Martial Artists, Lin Xuankong has unfortunately transmigrated to this era, becoming a poor and sickly old man. However, with the help of the system Life Plate, his Talent and Comprehension grow stronger the longer he lives.And his much younger wife is a martial master...“That iron ball used to be Zhang Wu's knife. I squeezed it a couple of times, and it ended up like this! ” said his wife.“I hope you can teach me some Cultivation Techniques. As for the reward...” said Lin eagerly.

In the year 298 from the era of the gods, elementary school girls Sumi Washio, Sonoko Nogi, and Gin Minowa are tasked with an important mission. They are to become heroes and fight Vertex, a mysterious enemy that is attacking Shinju-sama, the god tree that protects Shikoku, the only area in the world that is still habitable. What they don’t know, is that this fight will cost them more than they could have ever imagined.