Project Tokyo Dolls: Boukyaku no Imitation Doll

The year is 2017, in the city of Tokyo an idol group known as DOLLS is fighting against extraterrestrial monsters known as Pygmalion. Those who get attacked are deprived of their emotions and memories. If they're consumed, their very existence is wiped from the minds of everyone and the world itself. The girls who died and became "dolls" are the only ones capable of fighting against the Pygmalion threat. Another doll suddenly appeared before the girls during a battle, who in the world is she!?

(Source: Square Enix, translated)