What if Elmiryam Reincarnated into a moden world?

Elmiryam was originally the hero of a fantasy world. After agreeing to a peace with the Demon lord, they both sacrified themselves to end the war and create peace in the Empire, with the clause that both would be Reincarnated a thousand years later. However, something went wrong, and the hero Reincarnated in a modern world, and... in the body of a woman. After getting used to this world and to her new body, and deciding to study in a prestigious university, she got a job in a very big company, and, after very little time, she got promoted to an executive position. And it was during her first meeting in this new position that she saw the CEO for the first time, recognising him: it was the former Demon Lord.