Jonathan Custer was the caretaker of purgatory. As time went on, souls became more clearly defined as good or evil, and thus the population of Purgatory dwindled. He was one day approached by an angel, Kymberli, and told that Heaven would soon repurpose the space.
After a failed attempt to find new undefined souls, Custer returned to Heaven and the gates of Purgatory were closed forever. Kymberli returned to take it from him, and even though Jonathan Custer attempted to turn around purgatory, it was still taken.