Answer:
You bind me and I walk. You loosen me and I stop. What am I?
I'm as simple as a circle worthless as a leader; but when I follow a group their strength increases tenfold. By myself I'm practically nothing.
I am known for my natural tuxedo and marching
I march before armies, a thousand salute me. My fall can bring victory, but no one would shoot me. What am I?
I go from house to house a messenger small and tight. Whether it rains or snows I sleep outside at night.
Dark, feathery, and popular in Baltimore and fantasy books.