Riddle of the Iridescent

Alrighty, third time's the charm. Last one may have been a slight too concise, so I'm putting a red herring or two in this one, hopefully it's not solved too quick. Who/What am I? [i]I am all, and I am none. You use me, I use you, I carry you, and you carry me, I am whatever I need to be. I am the light, I am the flow, ask the cryptarch, he'll surely know. In the bone, and ash, I rise to complete my task, used, and dejected, everywhere, but never enough to rest complete, even though none others may even compete.[/i] Who/What am I? (Felt like rhyming this one sorta, why not? :p)