John says that Satan was the motivator in Judas' betrayal of Jesus, but we're best to understand that to mean that despite all the time Judas had spent in Jesus' company, he had not committed his will to Jesus. Judas was not Jesus-possessed, the Gospel of Judas notwithstanding.
The Gospel of Judas has been reexamined and again found to be authentic. By analyzing the unique ink used and how that ink interacted with the ancient papyrus, scientists concluded anew that the document is genuine.
Gospels about Jesus once flourished. However, one of the competing sects finally declared victory in the fourth century when it decreed that its four Gospels were the standard for the church Jesus founded. Or so the conspiracy theory goes.