Answer:
What turns from red to black as soon as it touches water?
Tall in the morning, short at noon, gone at night. But I'll be back soon.
Face with a tree, skin like the sea. A great beast I am. Yet vermin frightens me.
Sharp and long, flag of the world. What is it?
I cut through evil like a double edged sword, and chaos flees at my approach. Balance I single-handedly upraise, through battles fought with heart and mind, instead of with my gaze.
If it’s information you seek, come and see me. If it’s pairs of letters you need, I have consecutively three. What am I?