One member of Team Flash finds out who Savitar is on The Flash, but it might not do the team any good. In "The Once and Future Flash," Caitlin, having almost completely transformed into Killer Frost, runs away from STAR Labs and heads straight for Savitar. Savitar welcomes Killer Frost with open arms and tells her he wants to do something for her: make sure Caitlin Snow never comes back. When Caitlin replies that she needs a reason to trust him, Savitar reveals the man under the armor. Seeing who he is, Caitlin agrees to do his bidding, and that's when the episode ends. Caitlin's eagerness to join Savitar after learning his identity has a lot of fans wondering: Is Ronnie Savitar on The Flash?
Based solely on Killer Frost/Caitlin's interaction with Savitar at the end of the episode, two things are evident: 1) Savitar is, indeed, a man inside an impressive suit of armor, and 2) Caitlin trusts Savitar implicitly. Looking back at the past few years, there have only been a few characters Caitlin has trusted completely, and on the top of that list is Ronnie Raymond. Ronnie was Caitlin's true love, and his ambiguous death at the beginning of Season 2 definitely leaves the door open for a potential return. Furthermore, as seen in Earth-2, Killer Frost had her own version of Ronnie whom she loved, meaning she'd trust Ronnie as both Caitlin and Killer Frost.
I know what you're thinking: What about Cisco or Barry? Well, thanks to Barry's trip to the future in this episode, it looks like we can rule out Cisco and mark Barry as "unlikely." Both men are present and broody in Barry's trip to the future, which was apparently a time when Savitar was locked up, meaning it can't be either of them. (Granted, we don't really know much about Savitar or how his powers work, so, we'll put Barry's fate as TBD.)
On the off chance that Savitar isn't Ronnie, it also seems likely that he would be the original Season 1 Dr. Wells, as in Eobard Thawne. As the God of Speed, it seems unlikely that a little thing like death would keep Wells/Thawne/Reverse Flash down for long. It's possible he's just been living in the Speed Force, gaining strength, waiting for the right time to strike and ruin Barry's life as he always intended. The evidence here is a bit thinner: Savitar calls Caitlin "my child," and we all know Wells was very paternal towards both Cisco and Caitlin.
Hopefully, Savitar's true identity will be revealed sooner rather than later.