Chuck Shurley

Chuck Shurley is God, disguised as a human writer, who chronically records every detail about the lives of Sam and Dean Winchester. He, however, does not know that Sam and Dean are real until they actually introduce themselves. The headaches he receives give him visions about what the Winchester brothers have done. Because of these vision, he writes books about them, each book telling an episode of the series. Also, because Chuck is a prophet, an archangel, who demonstrates powers strong enough to scare even Lilith, becomes his guardian.

It is revealed in Swan Song that Chuck was the alter ego of God the entire time, and after completing the final chapter in the story of the Winchester brothers' quest to avert the Apocalypse, smiles and vanishes into nothingness after noting that "nothing is really too hard", revealing his true nature as God Himself.

Season 4

 * "The Monster at the End of This Book"
 * "Lucifer Rising"

Season 5

 * "Sympathy for the Devil"
 * "The End"
 * "The Real Ghostbusters"
 * "Swan Song"

Family
The Archangel Raphael (Guardian)

Becky Rosen (Chuck's number one fan; according to her, this has yet to be proven. And a possible girlfriend)

Mr and Mrs. Shurley (Parents)