so in future, Barry create remnants to kill original SVT and succeeded.
One remnant remain alive, but was shun by the team and turned to bad remnant(knn such lame excuse to become a bad ass)
Bad Remnant travel back to past and become new SVT combined Barry for revenge.
But how Bad remnant can become SVT?? unless he can kill original SVT on his own in the past which is impossible since future Barry need many remnants to kill original.