Elaine Pagels
Pagels was active in the discovery and the translation of the Gnostic texts in Egypt. She and a team of international researchers helped recover the documents, and translated them, as well as interpreting them. In the novel,. Pagels acts as the explanatory medium for the documents, saying the the Gnostics were different from traditional Christians in that they didn't allow people to simply convert, and they didn't like the overwhelming amount of power that the Church had at that time.
God
God is seen as a powerful figure in the Gnostic texts, even though he is not directly a character of the book. In Christianity, God is seen as the only divine being, and his son, Jesus, came down to Earth to spread his word. The Gnostics believed all of this much like modern Christians, but they did not like the Church. The Gnostic Gospels explain that the Church is too powerful, and this will limit people from professing their true faith in God in the way that He wants.
The Orthodox Church
Here, the Orthodox Church is sort of the antagonist. The Gnostics don't believe in their ways, and their texts were written specifically to defy them. Furthermore, the Orthodox Church retaliated by burning or otherwise destroying many Gnostic texts, which is why the find of the Gnostic Gospels in Egypt is so important.
