Answer:
I am a sound made by felines when petted.
I am the ultimate killing machine used not once but TWICE I can be made by humans.
I am wood that is neither hard straight or crooked
I am all around, yet to me you are half blind. Sunlight makes me invisible and difficult to find. What am I?
I contain six letters minus one and you got twelve.
I never sleep yet sometimes I weep. I can get angry or just be happy. Wherever you go, I will follow. No matter what you do, I will be there. I cannot die. What am I?