Three wanted a baby
Unfortunately, the Intoners are sterile (so they don't have to worry about babies or anything), possibly due to an Immortal Procreation Clause. Cue Three & her fixation with 'dolls'.- Jossed. Seere and Manah are descended from One.
- Yes, but from Brother One, who is only a pseudo-Intoner.
Accord is a newer model of Devola & Popola
Through time shenanigans, Accord robots are able to record their findings of the past. Devola & Popola are prototypes. When The Flower has to create multiple hosts for itself, it manipulates them into naming themselves after numbers.
- It makes it easier for The Flower to keep track of them. After discovering the naming scheme later on, Zero renamed herself Zero to mock the others.
Zero is Red Eye.
Considering that's what the leader of the Legion is known as, it makes sense that it could potentially be Zero reincarnated. Mikhail would have to put Zero down once more. Alternatively/In addition, Zero is the Queen Beast at the end of Drakengard.
She's just lost her hair over time. "The Great Disaster"/"The Cataclysm" happened as payback from God for the humans killing Jesus.
Hence the whole "pillars of salt" thing in Nier that was ultimately caused by the Cataclysm in Midgard. Zero is an Abyssal Exalted.
Eerily beautiful Blood Knight reanimated on the brink of death by an evil force that compels her to destroy the world. Terrifies ordinary mortals with her superhuman resilience and resemblance to the more heroic-seeming god-kings that rule the world. Changed her name after being forcibly melded with an Abyssal spark, which in this universe took the form of a flower. She ticks all the boxes. The Watchers are probably a Deathlord's coterie.
"The Great Disaster"/"The Cataclysm" is caused by events in the Nier Timeline.
The supplementary book Grimoire Nier mentions in its timeline that during the centuries leading up to the events of Nier, the Replicants and Androids purify the world of the Maso particles left behind by the Queen Beast and "send them to a parallel world" in a ceremony conducted in 3287. Perhaps this is the cause of the "great disaster" of the Drakengard timeline; the replicants and androids sent a city containing all the Maso they collected back in time into Drakengard's world. The "Black Flower" seen in the Utahime 5 manga, and implied to be the source of the Flower and Intoners from D3, may be the conglomeration of the Maso particles collected and sent back from the Nier timeline. Which would make the entire series one big multiverse time loop. Accord is an android from the Nier Automata era, sent back in time to observe history and possibly find a way to change the timeline to avert the events of Nier and Automata
Pretty self explanatory. With the Nier timeline pretty much ending with the entire extinction of humanity, and eventually androids and machine as well, it's pretty much a dead end. Accord may have been designed as a successor to Devola and Popola (hence the same voice actors for them), perhaps as an atonement for their mistakes, and sent back in time for the purpose of observing history and trying to find a timeline where the events of Nier can be averted.