Devola

Devola is the older twin sister of Popola, and with her shares the administrative duties of Nier's village.

She is also the town bard, and is often seen at the spring near the library, singing and playing her guitar. She gives performances in the local pub as well, and sometimes in a duet with her sister.

Like Popola, her name derives from the weapon Devolapopola found in the original Drakengard.

It is later revealed that both Devola and her sister Popola are android observers for Project Gestalt.

NieR:Automata:

New models of the twins exist thousands of years after the events of NieR. After the death of the Shadowlord, the original Devola and Popola models were blamed for the failure of Project Gestalt, and in turn the remaining models were reprogrammed to harbor constant feelings of guilt.