Annunaki = children of An.

An is the name for the Sumerian father deity, the god of heaven and father of the pantheon.

Annunaki was the name that refered to both the celestial choir of deities that were worship, and the name of the mortal children of An. Kind just alluded to, but we have so little. Basically these mortal children were set above all mankind as their leaders and guides. (strangely it specifically does not say rulers, and the way it does refer to them the context makes it seem as if they are just there to assist and direct, keeping humans heading in the pre-determined direction.) The Annunaki, in Babylonian and later Judeaism, become what what was called Nephilim. which first occured in babylonian mythology, the later in the judaism mythology.

Although if you go looking for nephilim, you actually have to find the babylonian stories and read them, as the internet and wiki only refer to the later reference from the bible. typical. Hope that answers who the Annunaki were/ possibly are for you.