Answer:
Mouth up it gets filled, mouth down it gets empty.
Your computer\'s version of white-out.
Four kings of whom I am one lord. Often on deck but never on board. Though I have a large heart, I am always seen at war. During which I always wear a suit, but never a suit of armor. Who or what am I?
What has a head and a tail but no body?
My second is performed by my first, and it is thought a thief by the marks of my whole might be caught.
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?