I read Machievelli's masterpiece, The Prince, many years ago.  I remained impressed ever since.  It would appear that I'm not alone.  Many politicians and dictators kept, and still keep, it by their bedside. These included Tony Blair and Josef Stalin. The Prince advocates ruthlessness when dealing with matters of state. It's better they fear you than love you. Love is two-sided and one side can abandon it for his or her own selfish needs. Fear is one-sided. Only the master (or mistress) controls it. Thus in the Game of State, as in the Game of Thrones, fear is a more powerful tool of control in the longer game.

For people writing fiction in which power is a major ingredient, understanding Machievelli is an important aid.  Readers of the same fiction will understand it better too if they understand the advice given to Renaissance Italian city princes.

Do I use it in my fiction, such as the fantasy series The Three Powers? What does the word Powers imply? Would the Tyrant of the Wastelands in The Snowmelt River understand Machievelli?

He probably inspired him.