Androids are a recurring race in the NieR / Drakengard Series. Their purpose varies by game.
Project Gestalt Edit
|Weiss, you dumbass!|
SPOILER ALERT - Plot details for NIER follow.
For Devola and Popola's part in the extinction of humanity, nearly all other models of Devola and Popola were destroyed, with the exception of the two that appear in 11945.
|That is why you, the YoRHa forces, exist:|
SPOILER ALERT - Plot details for NieR: Automata follow.
YoRHa is an operation that resulted in the production of a special type of android several years prior to the events of NieR: Automata. It is revealed that the true purpose of YoRHa is to perpetuate the lie that humanity is still alive, despite having gone extinct thousands of years ago as a result of Nier killing the Shadowlord. The announcements heard throughout the game is actually a recording made by YoRHa to make others think humanity is still on the moon. This revelation causes A2 to defect from YoRHa prior to the events in Automata.
It is also revealed towards the end of Automata that YoRHa android's Black Boxes are actually made from the cores of machines, as it was deemed inhumane to use traditional androids in the project, as the intention was to kill every last YoRHa unit once the machines were defeated. This, along with humanity being extinct and 2B's death, causes 9S to fall into insanity by the end of the game.