Answer:
Cold head and feet; round as a ball; always turning around myself.
I'm a ruler with 12 agents. Half of them work in the darkness. Who am I?
I cannot be burned in fire or drowned in water. What am I?
What goes through towns and over hills but never moves?
People buy me to eat but never eat me. What am I?
Whoever made me don't want me. Whoever bought me don't need me. Whoever use me don't know me.