This reader's opinion is that argonians are a product of the Hist, used to be able to interact with the outside races, and give the Hist a weapon to defend itself with.
I understand, so you think that argonians were created by the hist but are not biologicaly related to them. I suppose the hist were probably tired of the wars between the Ehnolfey and created the argonians or granted sentiance to Black Marsh tree lizards in order to have more sway on the world around them? Let me revise my diagram:
:frog:
:dance: (just ignore the face there)
^
:shocking: x :frog:
^
Hist
This Means :poke:
(The yellow guy is the hist, the stick is an argonian (kind of like a tool) , and the blue guy is an Ehnolfey)
:celebration:
________________________
Hist + Hist x 900000 generations = :frog:
:huh: