One would have to make some sort of survey to answer the question regarding the two alternatives offered, by the question, regarding Christians.

To my own mind, it is clear what Jesus Christ's values were in that his most vigorous and his most comprehensive censuring was against neither of the above but against hypocrisy. I can think of no stronger words which he uttered on this earth which were so condemnatory against particular characteristics.

Jesus of Nazareth pronounced an eight fold 'Woe' (a witness to the four corners of the earth) against the leaders of religion, in the days of his flesh upon earth, which leaders held the outward positions of religious power over the people yet rejected the real kingdom of heaven, selfishly coveting their own power and their own position despite that it was sheer hypocrisy for them to maintain it in the face of the witness of both John the Baptist and Jesus of Nazareth to their falsity and their greed and their covetousness :

But woe unto you, scribes and Pharisees, hypocrites! for ye shut up the kingdom of heaven against men: for ye neither go in yourselves, neither suffer ye them that are entering to go in.

Woe unto you, scribes and Pharisees, hypocrites! for ye devour widows' houses, and for a pretence make long prayer: therefore ye shall receive the greater damnation.

Woe unto you, scribes and Pharisees, hypocrites! for ye compass sea and land to make one proselyte, and when he is made, ye make him twofold more the child of hell than yourselves.

Woe unto you, ye blind guides, which say, Whosoever shall swear by the temple, it is nothing; but whosoever shall swear by the gold of the temple, he is a debtor! 17Ye fools and blind: for whether is greater, the gold, or the temple that sanctifieth the gold? 18And, Whosoever shall swear by the altar, it is nothing; but whosoever sweareth by the gift that is upon it, he is guilty. 19Ye fools and blind: for whether is greater, the gift, or the altar that sanctifieth the gift? 20Whoso therefore shall swear by the altar, sweareth by it, and by all things thereon. 21And whoso shall swear by the temple, sweareth by it, and by him that dwelleth therein. 22And he that shall swear by heaven, sweareth by the throne of God, and by him that sitteth thereon.

Woe unto you, scribes and Pharisees, hypocrites! for ye pay tithe of mint and anise and cummin, and have omitted the weightier matters of the law, judgment, mercy, and faith: these ought ye to have done, and not to leave the other undone. 24Ye blind guides, which strain at a gnat, and swallow a camel.

Woe unto you, scribes and Pharisees, hypocrites! for ye make clean the outside of the cup and of the platter, but within they are full of extortion and excess. 26Thou blind Pharisee, cleanse first that which is within the cup and platter, that the outside of them may be clean also.

Woe unto you, scribes and Pharisees, hypocrites! for ye are like unto whited sepulchres, which indeed appear beautiful outward, but are within full of dead men's bones, and of all uncleanness. 28Even so ye also outwardly appear righteous unto men, but within ye are full of hypocrisy and iniquity.

Woe unto you, scribes and Pharisees, hypocrites! because ye build the tombs of the prophets, and garnish the sepulchres of the righteous, 30And say, If we had been in the days of our fathers, we would not have been partakers with them in the blood of the prophets. 31Wherefore ye be witnesses unto yourselves, that ye are the children of them which killed the prophets. 32Fill ye up then the measure of your fathers.

Ye serpents, ye generation of vipers, how can ye escape the damnation of hell?

Matthew 23 : 13-23 KJV

No. Christians are followers of the Christ (i.e., Jesus, the King). If a group does not do that, it is not a Christian group.

First off, I like your question because it made me think. Second, no answer can be given that does not also make as many assumptions as your questions. This answer assumes Biblical Inerrancy, a traditional timeline for the writing of all the books, and the assumption that not much editing has occurred between when the books were originally written and today.

1. Did the Old Testament always have a concept of Satan or was it added later?

From a literary standpoint, themes related to Satan run from beginning to end. The only addition is of depth, scope and detail. The first promise of a savior is in Genesis 3:14-15, and that is spoken directly to the serpent. The last reference to Satan is in Revelation, the last book of the Bible.

One place where you can argue that information about Satan was added later is in Job. The literary structure implies that Job is unaware of Satan’s involvement in his suffering, so that detail must have been added later. Tradition holds that Moses wrote down the Book of Job a few centuries after its event occurred. Another view is that Joshua, Moses’ scribe, who finished writing the Pentateuch after the death of Moses, wrote down Job. There are a few phrases found only in Job and Joshua, supporting this view.

Job is interesting because one of his first statements in his complaint is:

May those who curse days curse that day, those who are ready to rouse Leviathan. (Job 3:8, NIV)

God describes Behemoth (a terrestrial monster) and Leviathan (an aquatic one) in detail in Job 41. Then in Revelation 13, two beasts, one from the land and one from the sea, are described. Commentators mostly agree that those two beasts are Behemoth and Leviathan, and the latter is Satan. This makes the final chapter of the first book of the Bible to be written devoted substantially to a representation of Satan.

You might ask, why? Satan, the devil, Lucifer - serves several roles. He is adversary, accuser, liar and murderer. The Old Testament is preoccupied with God as a lawgiver. In a court of law you have the accused and the accuser, testimony and witnesses, criminal, victim and crime. Satan serves as the focus of lying to make false accusations in contradiction to God (especially Jesus) who is the truth. Satan falsely accuses and God forgives. Satan murders and God gives eternal life. Thus, from a literary standpoint, the presence of Satan makes sense. The worldview of both Old and New Testaments is that all things have logical causes and laws that govern them, hence there must be an origin of evil, lies and death, and a good God will reveal it to his people.

2. If so, why was it added? (For example some of the scriptures in the Bible that were present in Coptic scrolls in the Nag Hamadi library e.g. the "Exegesis of the Soul" were destroyed due to a clearout of suspected heretical material in the Bible that may have crept in over the centuries and so do not feature in the 1611 KJV many centuries later.)

My assumption is that it was not added, except as I described concerning the Book of Job.

3. Was it added because devout people were afraid to depict actions of God as being negative and they were scared of being seen to blaspheme?

The Book of Job and Ecclesiastes are each hard-hitting books that subversively question accepted wisdom and false religious ideas that attempt to give simplistic answers to hard questions. Job especially takes exactly the opposite tack of the one you suggest. After relating a conversation between God and Satan in which Satan is given permission to inflict catastrophe upon Job, God never lays blame on Satan in His answer in chapters 38-42. In Genesis, Eve blamed the serpent for her actions, and Adam blamed his wife. God blames no one for Job’s misfortune. He assumes full responsibility - even if that means bad PR for his religion, and Job accepts that and continues to worship that same God:

Then Job replied to the LORD: “I know that you can do all things; no purpose of yours can be thwarted. You asked, ‘Who is this that obscures my plans without knowledge?’ Surely I spoke of things I did not understand, things too wonderful for me to know. “You said, ‘Listen now, and I will speak; I will question you, and you shall answer me.’ My ears had heard of you but now my eyes have seen you. Therefore I despise myself and repent in dust and ashes.” (Job 42:1-6, NIV)

4. If Satan is there to carry the burden of all evil within the world, are actions such as the anger of God in the old testiment, good or bad, or neither?

The Bible distinguishes between God’s anger and man’s.

My dear brothers and sisters, take note of this: Everyone should be quick to listen, slow to speak and slow to become angry, because human anger does not produce the righteousness that God desires. (James 1:19-20, NIV)

God’s anger is foreseeable, justified and proportionate.

It is foreseeable, because God gives us His laws so we know what to expect, he does not change them without advance notice, he reveals his future actions via His prophets, and then when the time arrives, He executes His judgment as promised.

Surely the Sovereign LORD does nothing without revealing his plan to his servants the prophets. (Amos 3:7, NIV)

It is justified, because God only punishes according to the truth, cannot be bribed, and does not show favoritism.

There will be trouble and distress for every human being who does evil: first for the Jew, then for the Gentile; but glory, honor and peace for everyone who does good: first for the Jew, then for the Gentile. For God does not show favoritism. (Romans 2:9-11, NIV)

It is proportionate. When God sent foreign armies to punish Israel and they overstepped their bounds and tried to cause more harm than He had decreed, He sent distress upon those nations, too.

Israel was exiled for seventy years. They had failed to faithfully honor him on the Sabbath for 490 years, so one seventh of 490 is seventy. Their exile was measured out precisely.

God’s anger is not the anger of Satan who wants to kill. It is the anger of a father who wants to teach, admonish and straighten the path of His children so they will be perfect and can experience joyful fellowship with Him forever. Motive is important. Thus God’s anger is not evil or neutral, it is good.

5. Is there any clue in the Bible that gives indication as to why God's anger is not the responsibility of Satan?

Job finally accepts that the terrors assailing him are part of God’s plan to purify him:

But he knows the way that I take; when he has tested me, I will come forth as gold. (Job 23:10, NIV)

Paul reiterated this idea:

And we know that in all things God works for the good of those who love him, who have been called according to his purpose. (Romans 8:28, NIV)

A vital part of the theology of suffering is that God speaks to us in various ways, and one of those ways is suffering. If you look at all of Job’s speeches, you will find that he is publishing a job description for a savior, laying out all the troubles from which he needed God to rescue him. That job description matches point for point every things that Jesus eventually did. So Job’s suffering taught him what was needed in a Savior. Job recognized that he needed a savior with the power of God (could walk on water: He alone stretches out the heavens and treads on the waves of the sea. (Job 9:8, NIV)) but also the empathy of a fellow, suffering human, whom he called the “son of man”, a title Jesus would later adopt to describe himself:

My friends scorn me;
   my eye pours out tears to God,
that he would argue the case of a man with God,
   as a son of man does with his neighbor.
 (Job 16:20-21, ESV)

Job basically prophesied the incarnation!

6. Is there an official stance on this, and is it based on the scriptures, or by a figurehead, such as say a saint or a pope?

I have based my answer on Scripture. God’s anger surely has many purposes beyond those I have discussed, but most assuredly is a tool that He employs to strengthen our character and give us hope.

Not only so, but we also glory in our sufferings, because we know that suffering produces perseverance; perseverance, character; and character, hope. And hope does not put us to shame, because God’s love has been poured out into our hearts through the Holy Spirit, who has been given to us. (Romans 5:3-5, NIV)

Satan’s Role. It is one thing to say that Satan was not a later addition, but it certainly was an inclusion. The Bible has an author and that author had a purpose in including information in the Bible concerning Satan. Satan is not mentioned often in the Old Testament, and in the New Testament he appears most often as a symbol in Jesus’ parables. Those few appearances occur at crucial times.

There are only five conversations in the Bible where Satan is present. In one (Zechariah 3), Satan is told to shut up and does not get to speak. In two (Matthew and Luke) we hear the same story of Jesus being tempted in the wilderness by Satan, with a slight variation in the ordering of events, we we will count that as one. That leaves Genesis 3 (the temptation of Eve) and Job 1 & 2.

So we have three principal conversations:

• In Eden about 6,000 years ago (or more).

• In Heaven (discussing Job) about 3,700 years ago

• In the wilderness near the Jordan about 2,000 years ago

In the first, Satan speaks to the creation (Eve) to attack the goodness of the Father in withholding the Tree of the Knowledge of Good and Evil from her and Adam.

In the second, Satan speaks to the Father about Job, saying that the man will curse God if made to suffer. Since Job’s great prayer is that his words be written down, Satan is attacking the Word of God - Jesus. If Job failed and cursed God, then the Bible’s first book could never be written.

In the third, Satan speaks to Jesus about - what? Immediately prior to entering the wilderness, Jesus was baptized and the Holy Spirit descended upon him. The Holy Spirit is the Advocate (teacher that explains Jesus’ words) and Comforter (who helps us with our emotions). Satan tried to trick Jesus with lies and scare him into getting angels to help him avoid suffering, persecution and death. Satan was trying to get Jesus to lose his connection to the Holy Spirit. Later in his ministry, Jesus told Peter that Satan wanted to sift him as wheat. What was Peter’s big moment? When he delivered the keynote address on the day of Pentecost. Peter announced the arrival of the Holy Spirit to empower people, work miracles of healing and enable truth to spread to the whole world.

Take this all together, and Satan’s main appearances (apart from Revelation, the end) are to attack the Father, then The Son, then The Holy Spirit - to create division within the members of the Trinity and cause God to fall apart. Satan failed, but in this failure caused the clear Triune nature of God to be manifest.

I am sure that God had other reasons for including stories about Satan than these, but he at least had these reasons.