They created the original humans androgynous but the Elohims later separated the male from the female because Earth's environment was to violent for these beings, this was done in a huge mother ship, the Eden from the bible.
He encouraged the new beings to eat from hallucinogen plants following Luzbel (Lucifer) orders. The black race are the original Adams and Eves.
When the other engineers saw the unpredictability of the new race, they decided to abandom Earth because they thought the mission was a failure. They left Gadreel on earth when he was discovered of ruining the mission, until he corrects his mistake.
When he does, Gadreel creates a new race of beings called Sunkies, pacific beings that now live inside Earth's caves.
The Elohims came back to earth after thousands of years when other worlds of the same type UR as earth, civilizations created there, destroyed themselves and saw that Earth's race was surviving and evolving.
The Cosmic Plan mission continues here.