Based on the erotic game by Astronauts: Sirius.

It has been a year since the tyrannical Demon King was defeated by the six heroes of the kingdom. One of the heroes, King Golten, persecuted and oppressed the demons. Meanwhile, the Demon King's daughter Lapis visits the "jack-of-all-trades" Shigure with her maid, Kalmia, in order to rebuild her ruined castle. The reward is a beautiful woman's body. Thus, the man with the power of charm becomes the strategist of his master and servant, and begins his work to revive the demon tribe!!

(Source: parabook, translated)

Note: Includes 1 extra chapter from the e-book limited special extended edition