That makes my brain hurt. So let me get this timeline right: - We start in Kobal. 12 tribes go to the colonies, 1 leaves and goes to Earth. THe one that leaves and goes to earth are cylons. - These cylons build robots, who destroy the Cylons. - Our friends back in the colonies also make robots, who destroy them. - They escape and find their way back to Earth to find the 13th tribe. So, if the 13th tribe is cylon, then so are the 1-12th tribes. thus everyones a cylon?