Answer:
A dragons tooth in a mortals hand, I kill, I maim, I divide the land.
I'm the source of all emotion, but I'm caged in a white prison.
I don't think or eat or slumber. Or move around or fear thunder. Just like you I look the same but I can't harm you or be your bane.
With head without hair. With mouth without tooth.
What month of the year has 28 days?
What is always coming but never arrives?