The sons of Cain were, city-builders, inventors, kings, and pharaohs. An example is Tubal-Cain, the first metal-worker.

From my point of view, Cain was the good guy. The Old Testament has everything reversed, and the God of the OT is the Demiurge (who some call Satan). In the OT, God was supposedly displeased with Cain's offering of produce from the fields, but approved of Abel's blood sacrifice. Cain and Abel then had a conversation in the field, before Cain kills Abel. The substance of the conversation has apparently been censored from the bible, as there is evidence that there is a missing passage or two. I believe that Cain might have disproved of some of Abel's practices, including sacrifice (human, perhaps? I think it's likely). Who knows, but regardless, the OT has Cain killing Abel and being sent East, but still protected and somewhat blessed by God.

So Cain was agrarian and Abel was a shepherd. The agrarians were city-builders and dwellers, and the shepherds also became merchants who traveled from city to city. There was often conflict between these two groups. Some even believe that the shepherds had closer ancestry to and were descendants of Neanderthals, while the agrarians were descendants of Cro-Magnons, but I digress...

Cain is also Osiris of Egyptian mythology, who is killed by his brother Sett (likely Seth of the bible). I think it is important to note that the Hyksos were Hebrews who invaded Egypt and in many cases worshiped Sett.