I am gonna assume that at some point in the near future Reverse-Flash becomes the Flash's arch-enemy and after getting beat by Barry a bunch of times he decides to go back to the past to kill Barry before he got his super-powers.jaw dropping episode. Show is really operating on another level.
Why did wells want to kill Barry initially? Especially from so far into the future?
Chronologically the Reverse-Flash has yet to have his first encounter with Barry yet.