How Did the Demon King Reincarnate and End Up Surrounded by Magical Girls?

An ordinary college student is unexpectedly whisked away by a goddess to another world. At long last, he completes the ridiculous task of becoming a Demon King and getting defeated by a hero. It seems he can return home in glory with the reward the goddess gave him. But wait, what does she mean by saying he has to get used to his old life as an ordinary person first, and spend a few years in a world with little magic? Hey, hey, I still have all my powers from when I was the Demon King. How long do I have to prove I can resist using them before you’ll let me go home? Huh? Is this world full of soft, sweet magical girls? Heh, Goddess, you said that once I completed the task and went back, I’d return to the exact moment I transmigrated, right?