The Reverse-Flash returns in the eleventh episode of season 2, conspicuously titled.... "The Reverse Flash Returns". When this news broke, many fans theorized that we would be seeing an Earth-2 version of the character as the alternate reality has already presented viewers with several Central City doppelgangers. However, executive producer Andrew Kreisberg states that's not the case for The Flash's season one nemesis. "Time on our show does not unfold linearly. Sometimes you’ve seen events from one direction and then you start to see them from the other. This Reverse-Flash is not exactly the Reverse-Flash that we saw disintegrate at the end of the year. It’s a Reverse-Flash from an earlier timeline. It’s not the Earth-Two Reverse-Flash, it’s the Reverse-Flash. That is, hands down, one of our best episodes."
How does the Reverse-Flash return from an earlier timeline? At some point during season one, does the Reverse-Flash race to the future to see how his evil plan turns out? Does Zoom pluck Reverse-Flash out of the past to torment Barry in the future.
We'll have to wait until the Reverse-Flash returns in the January 26th episode of The Flash.