User blog comment:JMOfficial/Flash Big Bads in the Future/@comment-26618197-20170817204320/@comment-24152851-20170820012553

Eobard only became Reverse-Flash because of Barry, not our Barry the Barry from the original timeline. But due to needing him, Eobard ended up creating the Flash from our Barry's timeline. And apparently the Speed Force wants to remember the "Eobard kills Barry's mother" as the real timeline so Barry can't deviate from it.