“Why did it turn out like this!” I was working as a programmer at a black company, but I was hit by a truck and transferred to another world. At that moment, the soul of a sage took up residence in my head. The soul of the sage had something it wanted to accomplish. That was… “Defeating the Demon King” Ordinary me, under the super Spartan guidance of the sage's soul, spent 30 years becoming strong enough to be called a hero. And then, I challenged and defeated the Demon King!! “I guess the soul of the sage can finally rest in peace.” I was confident that I would be able to live a slow life in the other world, complete with a harem. But then, unexpectedly. The moment I opened the Demon King's treasure chest, I was sent back to modern-day Japan. And not just that, but 1 minute before I was hit by the truck. I couldn't bring back any magic or items, but the skills I had developed to defeat the Demon King remained. In modern-day Japan, a returnee from another world who defeated the Demon King shows his dominance in the business world. I haven't given up on the harem either. My dream is big, to start the world's number one company!