More than any past season, The Flash Season 3, the odds seemed stacked against Team Flash. Barry Allen has been moving at lightning speed, trying to change the future to save Iris, but there is a darkness surrounding this season, set up by the prophecy that one member of the team will fall, another will face a fate worse than death, and another will betray the team. All of this stems from the big bad of The Flash Season 3, Savitar. The "God of Speed" seems to know everything about Team Flash, but they don't even know who he is. One theory that's been gaining a lot of steam is that Eddie Thawne is Savitar — yes, Iris' old fiancé might turn out to be her killer.
There are many competing theories about Savitar's background, from a future, evil Barry Allen to any of the other team members. There's also the possibility that Savitar is a new evil, not connected to any of our main characters. Personally, I think Savitar is familiar because that's been the pattern of the show for the past three seasons. Reverse-Flash turns was Wells, Zoom was Jay Garrick, and even the Man in the Iron Mask was Henry Allen's doppelganger. It would be out of character for The Flash if Savitar doesn't have some kind of important connection.
The biggest that suggests Eddie is that connection has nothing to do with complicated theories or comic book backstories. It's simply that the actor who plays Eddie, Rick Cosnett, is back working on The Flash. Of course, there are many ways Eddie could return that don't include him being the major evil of the season. This is a world of multiple earths, flashbacks, Flashpoint, dreams and all sorts of magic. A character in a comic book world is only dead for so long (keep that in mind for the future). Still, the below photo that he posted to Instagram raises suspicions.
