What Am I Riddles

Question: Who hunts in a crowd, who hides in plain sight, who do you trust even though you don't know him?

Question: What laughs while stalking prey, but never goes in for the kill?

Question: I had a chance to be alive, but I am dead. I am white but some times brown. And most times when I open I feel like I'm burning as I face the sun.

Question: I break down buildings I crumble mountains You can't see me What am I?

Question: Eight of us go fourth, not back, to protect our king from an attack. What are we?