The Hero's Demon-Lord Slave

After conquering the world, the Demon Lord Animus one day discovered a door to another world. With her servant Lilim in tow, the demon set out to conquer this new world as well. The only problem? She overestimated her own abilities just a little bit too much...

In this new world, she's unable to use magic, and she and her maid are swiftly captured and sold into slavery. And who bought them, you may ask? Why, none other than that world's hero...

[From DLsite]