Board Thread:General Discussion/@comment-1781513-20170703143659/@comment-88.207.112.26-20171210070840

it's impossible to know, but the legend you refer to says that yu came to the world from the body of a dragon (mentioned in the series). that might suggest that yu arrived to earth inside the body of an unas, which he could have been inhabiting for however long. and it didn't need to be the first unas he ever inhabited.

as for ushu, I do not believe he served Yu under an impresion that Yu was a god see as Yu was the one goauld who did not refer to himself as one (mentioned in the series). It is difficult to say whether ushu's actions were driven by loyalty to a good master, or if at that point he was (ironically) using Yu as his own puppet, but that is why matters surrounding lord Yu are so interesting: being written in such an ambiguous way, it is impossible to tell, and this keeps one guessing.