>>97560556One day in Tokyo, an evil God in the shape of a giant woman crossed dimensions to crash in the city, followed by a man and a dragon who battled the God in a rhythm battle. The God perished, but the JSDF who scrambled fighter jets to intercept the threat ended up killing the man and his dragon.
However, the remnants of the evil God ended up infecting the human population with White Chlorination Syndrome, which would turn those inflicted with it into piles of salt. Worse still, some of those infected ended up resurrecting as salt golems, who went berserk and began attacking and infecting the population. Eventually the US got involved and attempted to nuke the problem away, which only ended up spreading the condition globally.
Eventually they found from studying the corpse of the dragon that both the dragon and the God possessed "maso," an otherworldly particle that was responsible for the WCS. It was found that the Dragon's maso counteracted the maso of the God, and so humanity was able to find a means of fighting back against the legions of salt golem created by the God. Eventually, humans realized WCS was caused by the God forcibly making contracts with the souls of humans, and in order to eradicate WCS, they developed a means to separate the soul from the body.
The separated soul became the Gestalt, while they managed to create bodies based on the soul's data known as Replicants. By putting the Gestalt in stasis while creating soulless androids to lead the shells that were Replicants to eliminate the God's maso from the world, the humans found a way to outlive the WCS. There was one problem, however, because the Gestalts had a tendency to become corrupt when separated from the body and it would become impossible to recreate their Replicant data from the Gestalt. This was the cause of the black scrawl disease.
To solve this, they needed a stable Gestalt from which they could pull the maso off of to feed the other Gestalts to keep them sane. Nier was that stable Gestalt.