Answer:
The eight of us move forth and back. To protect our king from the foes attack.
Two in a whole and four in a pair. And six in a trio you see. And eight's a quartet but what you must get. Is the name that fits just one of me?
Dies half its life. Lives the rest. Dances without music. Breathes without breath.
What I am filled, I can point the way. When I am empty. Nothing moves me. I have two skins. One without and one within.
What makes a loud noise when changing its jacket, becomes larger but weighs less?
A doctor might remove one from the neck of a Dracula victim.
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?