|Weiss, you dumbass!|
SPOILER ALERT - Plot details for NIER follow.
Project Gestalt (German: Gestalt – "essence or shape of an entity's complete form") was initiated to save humanity from the incurable White Chlorination Syndrome, which was spread by the maso, after the battle between The Dragon against The Giant. The humans would seperate their soul from their body until the WCS would vanish on its own and then rejoined again. Therefore, the soulless Replicants were created from the data of the genes of the human body and its corresponding soul was stashed away within the form of the Gestalts, also known as Shades in Nier's time of age. However, according to the protocolled data files, an uncalculated error occured during the transformation process, which made it possible that Replicants could become self aware, thus making a fusion with its Gestalt impossible. This effect is known as relapse, which not only turns the Gestalt hostile, but also affects the Replicant, in showing marks on its body: The Black Scrawl.
NieR: Automata Edit
|That is why you, the YoRHa forces, exist:|
SPOILER ALERT - Plot details for NieR: Automata follow.
It is revealed in NieR: Automata that as a result of Nier killing the Shadowlord, Project Gestalt failed. The result was that humanity became extinct within a thousand years. This event led to the creation of YoRHa, a project that's goal was to destroy all the machines and perpetuate the lie that humanity had managed to escape to the moon and survive there.