Rosen, a former psychiatrist, arrived in the simple Gotham City, entering Arkham, a place teeming with talent. In this timeline, Gotham is a peaceful city with zero crime?at least on the surface. But Rosen personally shattered this tranquility, plunging the city into the abyss. His inner guilt was awakened upon his arrival in this city?perhaps this is its allure. Here, he became a "kindred spirit" with the Joker and an "enemy" with Batman, roaming the city of crime.