Historically, I am referring to the Bolsheviks and then the Communist Party of the Soviet Union

Generally, a vanguard party is the forward segment of the population that is educated on and dedicated to the project of social revolution and agitates and organizes among the general population towards this end, and though it becomes something more administrative when it has control of the state, those two functions remain, as does the need to not (try to) compel the masses into something they don't want to do. There can be no benevolent tyrants, just educators who operate with the popular mandate.