ringleader

päätekijä A leader of a group of people, especially an unofficial group.
A person who starts and leads a disturbance (such as a riot), a conspiracy, or a criminal gang.

(ux)

A sort of naughty persons, lewdly bent, / Under the countenance and confederacy / Of Lady Eleanor, the protector's wife, / The ringleader and head of all this rout, / Have practis'd dangerously against your state...