A Hentai System in the World of Danmachi - Chapter 153 - 152 - Towards Rivira.

Time travelling from the majestic era after the Recuperation of Reiki, he became Kimura Kazuki, a 16-year-old high school student in Japan, one year before the Reiki Recuperation.

Tentatively, he set out to hone himself to the bone, burning candles at both ends to stockpile resources in preparation for the imminent Recuperation of Reiki. His goal was to be many steps ahead of all humanity when the time comes.

However, it seemed like fate had decided to play a cruel trick on him.

One year later, the Recuperation of Reiki… did not happen as expected.

- Description from Novelupdates

“You want to steal my genes then leave?” He grabbed her and tried to force her to hand over the child that was born three years ago.

Condition 1: One yellow scarf soldier rune is satisfied

Condition 2: Kill 100 rune monsters independently

Condition 3: 5,000 times of training to kill a pig with a knife is satisfied

Condition 4: 10 Spirit Talisman Pills are satisfied

Rune unlock upgrade.

Your source runes have been promoted from ordinary quality [Yellow Turban Soldiers] to premium quality [Yellow Turban Warriors]!

- Description from novelbuddy

This story is about the romance that blossomed between a beautiful princess and several courtiers, told through the various positions they experienced together.