If there is any element of Fringe that could be tagged as the series' main symbol it would be the Observers. A constant presence in the Fringe universe, the Observers only recently gained prominence in the series' overarching storyline, over the course of season 4.
As far as the content was concerned, there were some brief hints as to the direction Fringe season 5 might be headed – most notably seen in the episode titled 'Letters of Transit' – and now we have a new season 5 teaser that is definitely an Observer event.
In past seasons, the role of the Observer was simply to do as their name implies - to chronicle these "fringe" events and move on. That role changed when the Observers delivered huge revelations towards the end of last season, and in season 5, they are jumping out of the shadows and firmly planting themselves at the center of the story.
Unfortunately, aside from a quick summation of every detail passed down in regards to the Observers over the series' past four seasons, no new information is revealed. Like the teaser for season 5 that was released back in July, there is no footage from the currently-in-production season. We know that filming is well underway – although several unfortunate circumstances have halted production – so it's only a matter of time before real, substantial trailers begin rolling out.
There is, however, a brief tagline in the teaser that reads, "They are coming," which leads us to believe that the Observer takeover hinted at by Walter Bishop in the teaser will take center stage in season 5's narrative.
Some set photos made their way online this past week; they suggested Fringe was abandoning its current time period, but given the nature of the series' mind-blowing storytelling we wouldn't be surprised to see a ton of new timelines. For the most part, season 4 abandoned the past seasons' tendency to place viewers in a time and setting without truly revealing where they were, a quality that hopefully returns as the show runners tick down Fringe's final 13 episodes.
Mostly, though, we just want answers.
Fringe begins its final season on September 28th at 9pm EST on FOX.