Noun
vendetta - A blood feud in which the family of a murdered person seeks vengeance on the murderer or the murderer's family
As the final act of his vendetta against Rugen, Inigo pulled out his sword and said, "Hello. My name is Inigo Montoya. You killed my father. Prepare to die."
ringleader - Someone who is the main influence or motivator behind a particular action or event, especially a disruptive or controversial one.
The police managed to arrest the ringleader of the gang, who had coordinated the series of robberies across the city.