The Annunaki are an alien race that came to Earth at the dawn of civilization and enslaved the human race.
The Annunaki feared an uprising of humans. For this reason their weapons and technology were engineered to require alien DNA in order to operate as a fail-safe.
The Annunaki also realized they were greatly outnumbered and if humans rebelled they could overrun them by sheer numbers alone. They genetically engineered select humans who were deemed loyal to them. They imbued these humans with the alien DNA required to operate their weapons and technology.
Fast forward to current time. The Annunaki are no where to be found. Most of the descendants of the humans with alien DNA have no idea of the great power they have within them.
There are clandestine organizations around the world that are aware of this power and actively recruit those who wield it. They are either searching for the alien artifacts to keep them out of the hands of those who would misuse their power, or to use that power to place them as rulers of the world.