Your Nature is who you truly are, the essence of your self. Your Demeanor is how you present yourself to others. Both come from the same list.

• Architect: Your life is dedicated to creating things that last, have value beyond the immediate.
• Autist: You are very secretive, hiding as much of yourself as possible from others.
• Autocrat: You desire to be in charge, not to accomplish anything, but for its own sake.
• Avant-Garde: You desire strongly to be first with everything; be it news, fashion, or trends.
• Bon Vivant: You have no greater desires in life beyond having a good time.
• Bravo: You desire others fear and respect; others probably consider you a bully.
• Caregiver: You need to have others depending on you, to have people to care for.
• Child: You are still a child in spirit, and desire others to look after you.
• Competitor: You have a strong desire to win. You must be the best in everything you do.
• Confidant: You like listening to people, especially when they confide personal secrets to you.
• Conformist: You prefer following to leading, it's easy to go along with the rules.
• Conniver: It's always easier to get someone else to do what you want done.
• Critic: Nothing is perfect. You like finding the defects in things and people others have missed.
• Curmudgeon: You're cynical, pessimistic, and probably sarcastic.
• Deviant: You're weird. Unlike others.
• Director: You're a natural leader, with a true purpose behind your drive.
• Fanatic: You must have a cause to follow, something to give meaning to your life.
• Gallant: You love to impress others, you need them to be impressed with you.
• Jester: The perpetual clown, always making jokes to raise the spirits of others, or to hide your own suffering.
• Jobsworth: You are dedicated to routine, and try to avoid anything that will disrupt it.
• Judge: You are a natural mediator, and seek after fair resolutions to disputes.
• Loner: You prefer to be alone, and to solve problems by yourself.
• Martyr: You need to be noticed, and to sacrifice yourself for others.
• Masochist: You need to suffer, not for recognition but because it is what motivates and inspires you. The greater the pain, the more intense the experience.
• Optimist: You're always looking on the bright side, even in this World of Darkness.
• Penitent: You exist to atone for your sins. Your existence is a chance to make good what was bad.
• Perfectionist: You can’t abide imperfections, especially when those faults are in yourself.
• Poltroon: You are a professional coward, preferring to avoid trouble whenever you can.
• Rebel: You're very independent. "What you rebelling against?""Whatcha got?"
• Scientist: You approach your surroundings with a critical eye, always looking to make sense of the world around you.
• Survivor: You'll do anything to save your own skin.
• Sycophant: You don’t believe yourself to be strong or worthy; you must cling to others and earn their support to survive.
• Traditionalist: You like the old ways, the status quo. You resist changes. 
• Visionary: You are one of the rare few who sees beyond the mundane, and attempts to bring their dreams into reality.

These are not all possible Natures and Demeanors; just about any one- or two-word phrase describing a character archetype can be used as a Nature or Demeanor if you don't find anything here that suits you.