"...some few lucky people in one lucky generation which has learned how to do [manipulate mankind].” -- The Abolition of Man by C.S.Lewis
We may call such people "sociopaths." E.g.: Hucksters, top politicians.
As they get more powerful and arrogant, we may call them "psychopaths." E.g.: Idi Amin, Saddam Hussein.
As they seek to achieve absolute power, have we learned yet, have we the courage to call them "megalomaniacs?" E.g.: Hitler, Stalin, the New World Order.