"Belkar ascends to godhood" is one of the mainstays in speculation on how Belkar could avoid his death prophecy, but let's take a look at it anyway.
Bit of a nitpick, but I'm pretty sure a god could breathe if they wanted to, and Belkar seems the type to do that just to spite the oracle if he ever found out the prophecy.
Interesting idea, but probably unnecessary. Green arose already, we know of no reason it can't do that again without the involvement of the original pantheon. Besides, as you point out later on, how on earth did a fragment of Ares survive this?
Belkar has maybe a month left, I think. Bit fuzzy on the timeline but the new year is very close in comic time.
In short, this is one of the more out there ideas that have been bouncing around for a while now. But given Rich's track record of subverting expectations it could maybe happen. I'm just not going to put my quatloos on it: It would kind of cheapen Belkar's arc and feel kinda deus ex machina-y if it turned out he's part of a dead god and he goes off to recreate the pantheon in his own image while also resolving the snarl plot on his own without the dark one being involved.