Answer:
I am the key that is the hardest to turn
What is harder to catch the faster you run?
There's not a kingdom on the earth I haven't traveled over and over and though I know not whence my birth yet when I come you know my roar. I through the town do take my flight and through the fields and meadows green and whether it be day or night I neither am nor can be seen.
If a man carried my burden, he would break his back. I am not big but leave silver in my tracks. What am I?
I am a person who pretends to be someone else
When I'm born I fly. When I'm alive I lay. When I'm dead I run.