If power, in a Democracy, comes from the Bottom, from where do Autocrats get power?

If the power in democratic government comes from the many People at the Bottom, where does the Power in an Autocracy come from? Or, to put it more directly, how do Autocratic 'leaders' acquire the power of the political institution they purport to govern? In the Divine Right of Kings form of 'governing', it was never a secret. In dictatorial forms, power was wrested from the Top, conquered, or taken by force. They have no secrets either. But, consider how some Autocratic, Oligarchic, or Plutocratic forms of government acquire power and one has to consider the part played by the People. Why is that?; because these other forms of government 'purportedly' get their power from the People. Does that make the acquisition of power in these latter governments legitimate? Not necessarily! Every political entity has a Government, a social, an economy, a judiciary, a military, a geographical area, and many other institutions. These institutions all lie between the Top of government and the Bottom, where the people live. As an institutional way of doing things, they can be arranged and designed to 'reflect' the 'will' of the People in diverse ways. For example; In a Plutocratic form of government, its well known that the power comes from the Plutocrats. Period. So, if they are in power, how can they arrange the 'institutions' to reflect the 'will' of the People? That's the goal. Hence, even if the institutions are so arranged to reflect votes by the populace, in actual fact, its the Plutocrats who will design it that way, because, simply, they have the power. That's changing the terrain of the political to reflect a 'democratic' form of government, when in fact, democracy has nothing to do with the process. Plutocrats are not dumb, they're smart, but they are 'motored' by the medium of exchange, or stated differently, by 'money', not democracy.