Astro King - Shoukan Yuusha dakedo Kakyuu Nintei sareta node Maid Harem o Tsukurimasu!

Story:

After being transported to another world with all of his classmates, Yoshitsune was ordered to conquer the dungeon as a hero. While his peers were all reeled in and tamed by the offer of unlimited sex with the castle maids, Yoshitsune, a low-rank hero, devoted his cheat skills to getting more and more maid wives.