>> According to the Hebrew bible which the Christian bible was derived, Satan was an angel that at the gates of heaven spoke up against a soul that wanted to enter heaven with all of that souls bad past deeds. <<
That is not in the bible. It is, however, a bit of context that Christians need to know. When Jesus said, "A house divided against itself cannot stand," to charges he must be a demon to command demons, he was refuting the dualism which the Jewish authorities were supposing, and which Christianity inherited.
"Diabolos," from which we get the word "Devil" means "accuser."
BUT while the diabolos argued against the salvation of Man, he is defeated by the "paraclete," or "advocate," who is man's defense attorney.
In short, the Judge will come to rule the world. The devil has argued that Man is not worthy of salvation, but the paraclete will argue that he should be saved anyway. Praise be to God that the Paraclete has triumphed over the devil!
>> The last pope COULD be Satan as he will lead the unrighteous from the gates of heaven. <<
"I am the good shepherd," -- Jesus.
"Peter, tend my sheep," -- Jesus, appointing Peter to be Pope
"Simon [Peter], you are Rock, and upon the Rock I shall build my Church, and the gates of Hell shall not withstand it." -- Jesus, defining the duties of the Pope.
"Peter the Roman, who shall feed the flock amid tribulations" -- St. Malachy.
Hard to figure that the role of the Pope would be to lead the flock (the faithful Christians) away from Heaven.