* I think English is really lacking. "Planet" in this text is better conceptualized by earth here, but since this is not Earth, I cannnot say emerged from the streams of living earth*

Any suggestions on strengthening that aspect?

So what's the name of this planet? Why not simply substitute the name for Earth? This intro doesn't overwhelm with names, so including your planet's name might actually help to ground the reader in an alien place. Else, why shouldn't I just assume he's on planet Earth?

Greydon emerged from the streaming currents of the living planet into a cool dark pool recessed far beneath the surrounding cliffs I think this first line is wordier than it needs to be. Think about which adjectives really pack a punch. For instance "streaming" and "currents" is kind of redundant--currents already suggest movement. "recessed far beneath the surrounding cliffs" is also wordy. "Surrounding" is extraneous--if he's emerging into them, of course they are surrounding. A different verb might do more work for you. It was a familiar place; although the water was clear and sweet, the tinge of suphur sulphur or sulfurtraced across his senses and reminded him of the boiling geyser this had once been. The place where decades before he had dove dived--though now that I say that I'm not sure that's rightinto his destiny. He wanted to leave this place; he longed to unit unite?with the ebbing embrace of the planets planet'score once again. He dove beneath the surface and swam but the planet would not recieve receivehim rather than tell us what the planet doesn't do maybe it's better to tell us what the planet does do. How does it reject him? How does it prevent him from returning? Simply by giving him the need to breath?. His lungs burned for air, unnacustomed unaccustomedas he was for this need to breath, it frightened him all the more. His heart raced as he met the surface with a burning gasp. He knew he must face what he was sent here for.

So he is a creature of the planet interior, correct? It's a little confusing because you say he long ago "dived into" his destiny, which suggest to me his destiny is in the planet core. And yet it appears by the last line that his destiny is on the surface.

It's an intriguing opening. I think it's a bit confusing. It almost feels like your starting too late. The trigger has already happened. Something caused him to return to the surface. That's the crucial moment. When did he start realizing he needed air? What stirred him from whatever existence he was in? Reading this, I thought that he'd surfaced for the first time. But then he already can't breath underwater for long, so then I started wondering whether he'd been trying and resurfacing this entire time, and we're only stepping in in the midst of his attempts.

AP and New York Times style prefer 'dived' to dove even though it is accepted more widely in common usage. Although 'dived' doesn't work with the rhythm of the sentence.

I'm not sure what is meant by the 'streaming currents of the living planet'. Do you mean the entire planet is living or just the strata or level he is traveling through before emerging? This wasn't clear to me and took me out of the narrative as I struggled over the meaning.