What Am I Riddles

Question: I am a big threat to humanity,
but you wouldn't get rid of me even if you could.

What am I?

Question: I stand in one place yet I fill a whole room.
I can be filled with molten rock and come in every hue.

What am I?

Question: Half of those who read this riddle, I am your best friend.
I depend on you, but it's you I will defend.

What am I?

Question: I make up all literature, but I'm often sealed.

What am I?

Question: I supply the facts, but you supply the thoughts. I am also used to describe realistic droughts. My inhabitants are abstract as their places, And I provide details of their words & faces. I hold details in a very complex form, I may cause your mind to conjure up a storm. I hold many different views from different eyes, My facts can be hard to find; as if in disguise. I may tell of facts, but it may be theories I contain, I can inform, persuade, and can even entertain. I tell of a little girl, and of men chasing a whale, and only through me can you find the answer to this tale. What am I?