My wife's sisters want me to make a harem?!

«A few wives is a norm for Overlord such as you.» My wife’s sister said… Minato was your ordinary guy. He had his shop and led a happy life with his wife by his side. Should his wife be as ordinary as him, Minato would probably die as a happy man in sixty years! Alas, his wife was actually from another world, and she had fox psychique?! Their bedtime was actually dual cultivation, and the husband became Overlord due to it?! And what’s up with her sisters… falling in love with him?!