A Machiavellian hero is willing to do whatever it takes to achieve his goal, no matter the cost. He seems to lack a moral code or a true moral compass.

Here are some examples of Machiavellian heroes:

Tony Soprano from The Sopranos: The lead character in the drama and the boss of the Soprano crime family, Tony did pretty horrific things to remain at the top of his game.

Walter White from Breaking Bad: In an effort to provide for his family in a way his teacher's salary could not allow, Walt decides to manufacture meth after being diagnosed with lung cancer. Being part of a massive drug ring leads Walt down some dark roads, and he presses forward for five seasons.

Jack from Lord of the Flies: Though not the protagonist, he certainly puts up a fierce battle for the role and has some Machiavellian tendencies. Jack wants to be leader of this deserted group of school boys, no matter the cost. He even resorts to murder more than once.

Henry VIII (real life history): Sometimes the truth is stranger than fiction, and the rule of Henry VIII certainly seems to indicate that he had some Machiavellian personality traits. He beheaded two wives, had other marriages annulled, and beheaded some of his (former) closest friends when they failed to achieve the goals he had in mind. He was certainly considered a hero early in his rule, being described as attractive and accomplished. By the end of his life, he was a tyrant to deal with.