Answer:
A precious fluid, thicker than water.
I never was, am always to be. No one ever saw me, nor ever will. And yet I am the confidence of all, To live and breath on this terrestrial ball.
We are all around, yet to us you are half blind. Sunlight makes us invisible, and difficult to find.
My first master has four legs, my second master has two. My first I serve in life, my second I serve in death. Tough I am, yet soft beside. Against ladies cheeks I often reside.
What flies without wings?
If itβs information you seek, come and see me. If itβs pairs of letters you need, I have consecutively three. What am I?