Christ said
He was a murderer from the beginning, and does not stand in the truth, because there is no truth in him. When he speaks a lie, he speaks from his own resources, for he is a liar and the father of it.
"So the great dragon was cast out, that serpent of old, called the Devil and Satan, who deceives the whole world; he was cast to the earth, and his angels were cast out with him. (Revelation 12:9)He laid hold of the dragon, that serpent of old, who is the Devil and Satan, and bound him for a thousand years. (Revelation 20:2)"
Seems the end speaks about someone from the beginning. The author from the beginning is the same at the end.