The Anunnaki are a long lived species of aliens also known as Reptilians. Even though the Anunnaki were of many species, the Reptilians are those who dominated their Priest Class. Even though they looked like the other species physically, there is something inside that is cold-blooded to the extent is most resembles that of reptiles.
The other Anunnaki were split into twelve castes or guilds. Rather than being as one type of occupation, they were considered as tribes, though one family could dominate. As the Anunnaki are not immortal, they had to create “offspring” suited to this planet. They used some humans as breeding stock to create themselves as superior beings.
Over time, the Anunnaki became Giants with god-like powers to the inferior humans. Humans are their livestock, and in those days, were consumed by them. Particularly, the children. The offering of children as human sacrifices came from those days. Even with human DNA, the Anunnaki were educated from birth to see all other life as inferior.
Even though they enhanced themselves to look like giant, beautiful, and angelical humans, they were different. They used augmentation technologies to have what seemed super powers, so that the humans had no doubts that the Anunnaki were their gods. The humans loved them and lived and died at their convenience, as their slaves.
This lasted for tens of thousands of years, up until the attack by the Aryans. It was easy for the Anunnaki to redirect the humans into fighting the Aryans, as they had a disposition to fight amongst themselves, to entertain the Anunnaki. The Aryans had fewer numbers, but were relentless and assimilated many humans to fight for them.
When the Anunnaki realised that defeat was inevitable, they unleashed weapons of mass destruction. These caused a flooding on Earth, not just with water, but what is termed, a mud flood. This covered the Star Gates and what was left from the assault. Enough was preserved for humanity to bring back life forms and evolve themselves.