

It's also possible Palpatine is really the unnamed Sith apprentice who slew Darth Plagueis and stole the secret of cheating death. The implication, then, is that the Emperor either survived after all, or his evil spirit - a Sith equivalent of a Force Ghost perhaps, retconning the pre-Disney era's expanded universe concepts which claimed Sith could not become Force Ghosts - haunts the remnants of the Death Star. McDiarmid, of course, portrayed Palpatine in the prequel trilogy. If all of that weren't enough, at the Star Wars Celebration today with the cast and filmmakers in attendance, actor Ian McDiarmid walked out on stage to join the cast after the trailer ended.

Which, in turn, hints at Palpatine's presence in the film. That makes the final shot of a ruined Death Star and Palpatine's cackle seem tied into the climax of Return of the Jedi, with this being the rubble that film's Death Star on which the Emperor was supposedly killed. So the trailer has lots of callbacks and implications tying it to the film in which Emperor Palpatine supposedly died and the final Death Star was blown to bits. Likewise, the other footage in the trailer frequently reflects The Return of the Jedi, including Lando flying the Millenium Flacon with Chewbacca and letting out an enthusiastic laugh as they fly through hyperspace, similar to the scene of the narrow escape from the Death Star moments after Lando delivers the killing shot into the space station's reactor core. So that's an obvious hint of the Emperor's return in the film.
