Answer:
I'm blue, but when you see me I'm red. You don't see me too often. I'm there for you if you're hurt, but I'm good for you. What am I?
Used left or right I get to travel over cobblestone or gravel. Used up I vie for sweet success used down I cause men great duress.
The faster you run the harder it is to catch me
I think you live beneath a roof that is upheld by me; I think you seldom walk abroad but my fair form you see; I close you in on every side you very dwelling pave and probably I'll go with you At last into the grave.
I have a title and many pages. I am a genteel of genteel descent. I am a killer veteran of war. I am a slave to my lord pledged to his service.
It has no top or bottom, but it can hold flesh, bones, and blood all at the same time.