What is the most oppressive way to get a leader or police system?

I am writing a novel and I trying to wrote about the most evil oppressive government.I know the main leader follows a cultish religion where he is a god and each guard is into it as well.The gods kill the weak and protect the strong.They have the priest become posessed and eaten after 20 years of practice.The officials folkie none of their own laws and no one can say anything about it.I think either a monarchy(Caligula,vlad dracul,king Louie) or fascism by violent takeover(Lenin,hitler,sadam).What is your opinion?