Skye Bluedeer is a fallen angel currently residing in Purgatory.
Skye was one of the angels who sided with Satan during the war against God. When Satan was defeated, Skye, along with the other fallen angels, fell into Hell, banished from Heaven. For centuries Skye remained in the inferno, knowing that he had no excuses for his actions, that he had only himself to blame. Even though he wanted to return to Heaven, he didn't know how. One day, he finally asked God for forgiveness, and that he was sorry for what he had done. God took Skye out of Hell and put him in Purgatory, asking him, along with other fallen angels who had repented, to watch over it until it was no longer needed, and then he would return to Heaven. Until that day comes, Skye remains in Purgatory, but is content to wait forever if need be, for in his words, "Heaven is worth it."
Though a fallen angel, Skye has the ability to travel between Purgatory and Hell, as he went there to take Fnar to Earth for his second life. He also has the ability to know what is happening on Earth at any given time, including individuals.