The end times are full of war... this is correct. The Bible tells that this will happen. This does not mean that this is God's will, just that this is what will happen.
An analogy, poor as it might be, would be if your girlfriend started dating a guy that you knew was a cheating, lying jerk. You could tell her that the relationship would end in disaster and pain for her but does this mean that you wanted it to happen? No. You just know what the end results are likely to be.
The difference between this analogy and God is that He sees the end from the beginning perfectly. This knowledge does not usurp our free will. Why? Be cause we do not know what the end will be. It is still our choice. This ending is not the way it is "supposed to be". The will of God was that we would walk in a close, perfect relationship with Him.
In our pride and rebellion we, not Adam and Eve, have chosen to go our own direction which is a path filled with loneliness and pain. No, the end of things is not the way God wanted it from the beginning. It's just the way that it will be and how He will finally put things right.
To answer a second component to your question (If this is "satan'g doing" then why did it end up in the Bible)? The Bible speaks to many issues including what God's thoughts are toward us (Jer. 19:11), the relationship that God wants to have with us (John 3:16 - 18); how we are to treat others (Love your neighbor as yourself), and what interferes with all of that (sin). The Bible is historical, poetic, prophetic, anectotal, and personal. It encompasses all that God wants to share with us regarding our relationship to Him.
Satan and his desires, actions born out of rebellion, pride and sin are part of that history.