In which type of government does a single person have nearly total power to make and enforce laws, and rules primarily by coercion?

I believe the answer is: Dictatorship

In a dictatorship, there is no separation of powers in the government, so basically the leader has all the power to create all the regulations that He want. 
This leader usually would get away without scratch even if He kill his political opposition. One example of a dictator would be Adolf  Hitler