Surviving in Another World

After retiring in his original world, all he wanted was a quiet life, a wife, and a child. In another world, all he wanted was an ordinary job as a librarian, along with a wife and a child. But everything changed the night a mysterious young woman knocked on his door... Is the legendary contract with the Golden Demon King real or not? Does the otherworldly Book of Revelation that can break the contract even exist? What happened to the empire that vanished five hundred years ago? Was it the wrath of the gods, or is there more to the story? Two identities, two professions, one in the light, one in the shadows. The truth slowly comes to light! Everything is unexpected, yet somehow just as it should be!