Slave Harem in the Labyrinth of the Other World 異世界迷宮でハーレムを

From the introduction:

Slave Harem is a setting of might and magic, where a suicidal young man named Michio Kaga found himself after clicking on what he thought was an MMO. After his character creation, he found himself in a fantasy world not unlike many others. This world has many aspects one would find in an RPG, the story follows this man as he navigates through the world where magical dungeons called “labyrinths” which are filled with monsters called “demons” is a common hazard. Here he finds new confidence, love, and even some political drama, all of this despite his best effort to keep his head down. Now you too have been selected to join him and maybe others into this world of high fantasy.