A human world completely conquered by a reptilian species that in the distance could be mistaken for human. Up close of course the differences were unmistakable: to a human at least
Because of an inability to see in the spectrum we consider normal, they had trouble distinguishing between us and them. The heat signature was about the same; the shape size and all except for skin and some details such as a lack of body hair, ears, nose and some differences in head shape we were almost indistinguishable.
But a human would know.
They were a little darker than royal blue; with almost an alligator like pattern to their snake like skin.
There was a human resistance; but the blue snake skin creatures actually employed guard dogs of a sort. Humans trained to detect humans.
