What kind of psychological profile does one have to have to successfully wield power over others?

Initially, not too much is required. You have to familiarize yourself with the view that you are better than others. You are stronger than others who are weak, and it is the natural order for strong to exploit those who are weak.

If you're not fully satisfied with the drastic simpleness and savagery of this view, you got to compensate for it with good skills of rationalization: "I'm better than others because..."

(If you're really good at this, you'll even truthfully believe your subjects are better of this way - for how could they even hope for anything else?)

After you're convinced that it is your right and duty to subjugate others, there comes another important aspect which will hugely influence your success: the hunger for power.

Your hunger for power may build up slowly over time or it may grow fast. If it grows too fast and your feeding grounds cannot satisfy the growing hunger, eventually the tension cannot be maintained and you will fall back on consuming yourself.

Other parts of your identity keep a kind of perverted balance with your hunger for power. They stand in the way of power, but they also provide a goal for it.

Most importantly, you have to act on the impulse for hunger and savor the power of others as it fills your empty shell - until it becomes empty routine and insufficient to feel alive from it.