I suppose the answer to this question depends on what you mean by “real.” Most folks intend that designation for things that have their own, unique physical existence in the external world. So what you really might be wondering is whether or not Satan exists as an external being or entity somewhere “out there” in the world around us.
Not long ago, the blog of a French colleague dropped The Devil’s Fane’s name as an example of the atheistic path within a modern religion characterized at least since 1975 by a presumptive split between those who view Satan as primarily symbol/inspiration/metaphor and those who imbue the figure with a more concrete external reality. I have little doubt but that the impetus behind the mention came from my tweeted reply to that author’s share on Twitter of a recent blog from a solitary European Satanist in which she evinced for the new year her recent conclusion that the theistic/esoteric path is the righter one for her within Satanism than her former atheistic/rationalist commitment.
In my reply, I expressed disappointment at another’s turn away from atheistic Satanism, a disappointment stemming from a nagging conviction I feel that so much of what makes modern Satanism fresh and new and of vital importance stems from a consideration directly relevant to its atheistic nature.
While I am very much not in the business of telling others how they should or should not structure their personal Satanism, I offer my thoughts in the external link here as a further explication of my own Satanic path and a plug for the atheistic tendency within the movement.