Answer:
There are millions of me. I am very small but when moving fast I am deadly.
Inside a great blue castle lives a shy young maid. She blushes in the morning and comes not out at night.
He has married many women, but has never been married. Who is he?
I fly through the air on small feathered wings, seeking out life and destroying all things.
Turn us on our backs and open up our stomachs you will be the wisest of men though at start a lummox.
I am your mother's brother's only brother in law. Who am I?