What is the "Voice of the Hero", actually?

Most of the different voices come into existence every time LQ die. For example, The Smitten appears when you die trying to save the Princess, The Broken appears when you are defeated by the Princess, The Contrarian appears when you fully disobey the Narrator, etc.

However, the Voice of the Hero is the exception - he is always present since the very beginning of the story and in the subsequent chapters. What is he and his origins actually?