Touchy subject. An LDS seminary scripture (the next on our list) reads: "Pray always, that you may come off conqueror; yea, that you may conquer Satan, and that you may escape the hands of the servants of Satan that do uphold his work" (D&C 10:5). Well, seems like good advice to give LDS teenagers, but talking about the Devil in such blunt terms makes some people a little skittish. And who exactly are these "servants of Satan"?
Early LDS scriptures spoke directly of Satan rather frequently. Satan was Joseph's primary explanation for the loss of the first 116 manuscript pages of the original text of the Book of Mormon, delivered by Joseph to his scribe and supporter Martin Harris. According to D&C 10, "wicked men have taken them" (the missing pages) and "they have altered the words," which they did because "Satan hath put it into their hearts" to do so (D&C 10:8, 10). This threat haunted Joseph for years. In 1830, the first edition of the Book of Mormon carried a Preface written by Joseph that explained how "some person or persons have stolen" the pages "for Satan had put it into their hearts to tempt the Lord their God, by altering the words, that they did read contrary from that which I translated and caused to be written." This one-paragraph Preface refers to Satan directly four more times in explaining the loss of the original pages, which were not reproduced for the printed 1830 edition (or any later edition).
The problem is that there is no evidence to suggest any group of men, servants of Satan or not, ever stole the missing pages. Even sympathetic LDS historians affirm that the evidence points to the wife of Martin Harris, who was strongly opposed to her husband's involvement with Joseph and was on the lookout for ways to derail the project (see, for example, Allen & Leonard, Story of the Latter-day Saints, p. 42). Martin at length borrowed the manuscript to bring home to show his wife to win her over to the project. While in his home, stored in a locked desk in his farmhouse, the manuscript disappeared, never to be seen again. Harris' wife had motive, means, and opportunity.
The short Encyclopedia of Mormonism entry entitled "The Lost 116 Pages" has this to say: "The most widespread rumor was that Harris' wife, irritated at having earlier been denied a glimpse of the ancient plates, had removed the manuscript translation from Martin's unlocked bureau and burned it. Not long afterward, she and Martin separated."
As for a more general discussion of the LDS view of Satan, the LDS publication True to the Faith provides a quick overview in the article entitled "Satan," where he is described as "a spirit son of God who was once an angel," but rebelled. He is described as especially fond of coercion rather than liberty or free agency, but God nevertheless allows Satan to tempt us here on planet Earth. We can, of course, resist: "You do not have to give in to Satan’s temptations. You have the power within you to choose good over evil." Just so it's clear which side I'm on, I'll second the motion: Choose good over evil, folks.