First let me say that I love the title 'Tyrant of Stone' but have difficulty even typing the name of the god or his Sphere. We're cool provided you don't care if I (and probably most others) call him Ohan, but otherwise you might want to rename him something easier
Some thought your Sphere and Portfolio might be a little simple, but I don't. I think that it's quite elegant in that you can branch out in several directions and do many things from where you start, so you have flexibility whilst retaining some clear things to do in the first few turns. Specifically we imagine that one or two continents will be lifted up on a crab's back, since Stone as a portfolio will discount such landscape sculpting from 25MP or FP down to a paltry 12. Drinks on Ohan, everybody! He can afford it!
The Sphere acting as Galbar's crust and physically supporting it is an interesting take on how a Sphere can interact. It's not as huge or as obvious and Galbar would probably be the same if we didn't have his Sphere around to explicitly be the one that supports Galbar, but it's an interesting concept nonetheless. A shame that you didn't get to connect to the death god's Sphere as loki changed his mind.
We did speak about how you could probably do more with your Sphere, though. BBeast had some cool ideas, "He's got the opportunity to bend physics to his will, so he could do it. Does Ehomakwoi drive tectonic plates? Create mineral deposits?"
Obligatory nitpicking--we saw a typo. You're either missing an 'and' or the name of a third Sphere in this line, "Ehomakwoi has strong connections to several Chthonic spheres, most notably with the Abyss, the Pit of Trials."
The other GMs thought Ohan's personality would drive some interesting conflicts between the other gods. Personally I don't expect much conflict of that nature; however, I do think that this 'imperious' and self-righteous attitude will get very interesting once heroes, demigods, and mortal civilizations enter the equation. Either way, from both perspectives we saw potential, so we're interested in seeing how it actually turns out IC!
I do like the originality of the form and how he isn't a humanoid. Gives variety. You made a cool symbol, too.
Overall this is good. Approved with minor suggestions.