Answer: inciter

AnswerCrossword Clue
INCITERRiot starter, e.g.
INCITERMotivator
INCITERRabble rouser.
INCITERTroublemaker.
INCITERRabble-rouser
INCITERFirebrand
inciterone who incites (to arouse to action)
inciterto urge to action