Answer:
Angels and pilots work with me.
What gets sharper the more you use it?
I run around the streets all day. Under the bed or by the door I sit at night never alone. my tongue hangs out waiting to be fed during the day.
I am a busy worker who is a water mammal.
I'm a ruler with 12 agents. Half of them work in the darkness. Who am I?
Black we are and much admired. Many seek us if they are tired. We tire the horse, and comfort man, and turn White when we've fulfilled your plan.