According to The Verge on Saturday, though details of the J.J. Abrams' "Star Wars 7" plot spoilers are rather minor up to this point with content having been leaked online, currently there is now what could be some possible plot leaks to the movie. Keep in mind, if "Star Wars" fans would like to go into this film totally mindless of it's content, there is no need to read further, otherwise move forward with anxious eyes.
There appears to be a lengthy flashback that goes back to a point in time where Leia is slightly beyond being a young girl. This is explanatory to the idea that Carrie Fisher's daughter, Billie Lourd, having been cast in the movie. Also, there looks to be a flashback involving historical information involving the movie's villains, the Sith Inquisitors.
That being said, for fans who favor Sith Lords, the flashback looks to be taking on Darth Vader in his prime. So it seems, if rumors turn out to be true, he may also get some screen presence.
The brunt of the entire flashback that seems to be the meat and potatoes of the plot is portion of the film that leaves off from George Lucas' "Star Wars: Return of the Jedi" film. For those who remember that far back, the Empire is eliminated and rumors have spread about saying at this point Luke Skywalker is then abducted by the Sith Inquisitors. Keep in mind, these characters are never found in any of the six movies. Dsiney admits that these characters are non-canon as they are taken from the line of story books, video games, and other works that go beyond the movies themselves.
Sources mentioned the main villain is cyborg in nature with a description of a "human upper lip and a steel jaw." Also, mentioned is how the metal pieces tend to weave in and out of the Sith Inquisitor's stature. He is also seen clutching with his robotic hand Darth Vader's cracked helmet which is rather synonymous to that of the image tweeted by J.J. Abrams himself. This promotional Twitter photo was due in part of his UNICEF "Star Wars: Force for Change."