Answer:
It is greater than God and more evil than the devil. The poor have it, the rich need it, and if you eat it you'll die.
My life can be measured in hours, I serve by being devoured. Thin, I am quick. Fat, I am slow. Wind is my foe.
I can be written, I can be spoken, I can be exposed, I can be broken.
I scribble forms of the finest letter, And repel elements of the harshest weather. I am an arrow-aimer and a dust-breaker.
The higher I climb, the hotter I engage. I cannot escape from my crystal cage.
I start with T end with T and within me is T.