Did you not read my post in entirity. There is Vehk the mortal and Vehk the god. And I ask you, then who is a god. Is Akatosh a god, oh wait, he died. How about Shezarr, oh yeah. Kyne? No, she's dead. Ysmir? No, he's dead too. Since when did being a mortal bar a person in TES from being a god? That is why Ayem, Seht and Vehk were gods from the beginning, and are always going to be gods. And is Bar Daan still hanging over the city of Vivec, the prime of Vehk's godliness, still there. And doesn't the Clockwork City still exist, and Levitation still banned in Mournhold. If they were truely not gods, everything they had done as gods would disappear.
I would say that the bit about god from the beginning of time is folklore to make it easier to accept Vivec as a God. Even the Gods went from mortal to god and back to mortal.
So there really isn't anything that makes anybody a god except people willing to believe that there is one.