Reddit mentions of Satan: A Biography

That is, indeed, the gist. However it also depends on which gospel you read as they all spin it differently. In the earliest gospels Satan (not a name, in fact, but an adjective for one who presents obstacles) was simply an angel employed by God to test men's sincere goodness.

The character, who is not even one character, does not at first enjoy his work. But as humans were always annoyingly demanding to know why God would let harm come to them, the character solidified into one and was re characterized as a malicious creature that took pleasure in pain. This took place over centuries of successive addendums and revisions, and our modern image of Satan is largely derived not from the gospels themselves but from artistic interpretations from, if I remember right, the 15-17'00s.

Source: I literally took a class on Satan. Class text: Biography of Satan