Now that I've put Nietzsche into perspective for mankind , after about 120 years of failed attempts to do so , as a stenographer for the Spirits of Darkness at the dawn of the age of Satan, a.k.a. The New Age, I can see how Satan was using him to create the "philosophical" groundwork for organized Satanism.
Not many people notice the existence of what amounts to a vast conspiracy of humanoids who consider themselves to be Nietzschean "masters" (Google "Nietzsche master slave," without the quotes) who are fundamentally superior to the "slaves" which constitute the vast majority of mankind, or who have themselves been enslaved (as a result of their Nietzschean-Dionysian attitude/activity) by becoming possessed (Crowley's "Magick," including "sex magick," i.e. "orgy magick") by Satanic beings who have no vested interest in advancing the human race, and in fact are out to destroy it at the behest of their masters, Satan and his boss, the Devil or the Anti-Christ, which was the title of one of Satan-Nietzsche's last books. So, they're duped into becoming slaves by appealing to their egotism, by being told that they're superior, or masters (a specifically LUCIFERIC delusions-of-grandeur influence - the specifically Satanic aspect is being told that they're superior ANIMALS), and that masters are allowed to behave in a Dionysian manner, i.e. a combination of orgies among themselves and cruelty toward the "slaves."
We have been blinded to their existence with an epic disinformation campaign which has led to a variety of assumptions, such as that expressed in the mocking title of Darwin's late high priest Carl Sagan's "Demon-Haunted World." (It is demon-haunted, but it does no good to ascribe everything we don't like to them, and it's "haunted" by all sorts of spiritual influences which except for Satan's "underworld-lings" don't violate our free will by turning us into their puppets.)
Another one of these assumptions is that people try to be as good as possible while looking out for themselves.
This is precisely what Satan, wearing Nietzsche as a mask, meant by "will to power": the willingness to abandon oneself first to one's instincts, egotism, and narcissism, and then to the anti-human impulses arising from the resulting "Jupiter man" form of Satanic possession, using whatever power one has to crush the "slaves" underfoot, "justifying" it with whatever excuse comes to mind. This is Nietzsche-Satan's "freedom."
Revision: Added notes below and final sentence above. Tweaked text in parentheses in third para. and deleted repetitive sentences at end of para.
 I couldn't have done it without standing on the shoulders of giants such as LaRouche, Rudolf Steiner, and the many scholars who have systematized and clarified Nietzsche's ramblings. I'm no genius - just someone who's had the opportunity to see the key pieces of the puzzle and isn't afraid to make claims that will seem nuts to a lot of people, at least at first.
 LaRouche's perspective was the closest - he called Nietzsche the prophet of the New Age, and he noted its Satanic nature and that Crowley supported Nietzsche.