Immanuel's life must be hell
I had some life circumstances interrupt my Automata playthrough (my ability to play video games in general, really) but I finally picked it back up on Sunday and found I had stopped midway through the Forest Kingdom (Route B).
I'm sure the thought must have occurred to me previously, but finishing out the Kingdom and getting the flashbacks to the Forest King and his coterie, it occurred to me that the King's life must have been a living hell.
The flashbacks are, first and foremost, funny. The machines are dumb. They admit to being dumb. They're trying their best but they're just mimicking the broad sweeps of humanity and don't understand much of anything. It's cute. It's endearing. You murder, like, a hundred of those guys just walking through the castle. It's cute.
The core of their flashbacks in the Forest Kingdom are pertinent to their King. Originally one of the larger forms of the robots (although technically speaking all of the robots are actually just little guys in varying chassis), he eventually runs down and is rendered inoperable, and the Royal Knights, unaware of what else to do, decide to take his memory and plant it in an infant, intending to raise him to be the new Forest King.
But also they're robots so they don't, like... grow up.
The machines are obviously capable of individual development-- they're all based on the Stubby design and they get bigger by bolting different parts to themselves rather than any kind of literal organic development. You can witness a few peaceful robots do this over the course of the game. But they put the Forest King, Immanuel, in a body that requires outside maintenance. Like an infant, he is unable to do anything but lay on his back unless another machine were to put him on his feet.. He has no arms. He is trapped in a defenseless body, barely capable of independent ambulation, while the Royal Guard watches over him.
If he were actually an 'infant', as far as the Machine Lifeform meaning of the word goes, I guess this would be... horrifying in its own way, but at least you could understand he was programmed to be a child. Except we were told that he was installed with the original King's memory. So actually this is a machine who lived a full likfe as a monarch and then got slotted into the form of a tiny, helpless baby, unable to do anything but make cute noises and waggle its useless feet.
For over a hundred years.
NieR: Automata is a game about robots fighting robots, but it's a story about existential philosophy and the purpose of meaning in a world that is, objectively, without a grander purpose. The Forest Kingdom arguably seemed to find some kind of purpose, with the King ruling and protecting his people and his Knights finding meaning by in turn protecting their King. Now the Knights continue to fulfill their function while the King has been stripped of his, and moreover put inside a body that is almost totally incapable of communicating that he is still present and no doubt wishes to return to his function, to oversee his people, but cannot.
A2 stabbing him might be considered a mercy in this regard. I'm sure you're all at least passingly familiar with I Have No Mouth and I Must Scream, where the evil computer AM's greatest torment is rendering the viewpoint character a helpless, blob-like creature, immortal by design and so soft and gentle by nature he is no longer even capable of taking his own life. So lies Immanuel in the prince's pram, stripped of voice and agency, his own Knights oblivious to the torment they have rendered upon him.
But he sure is a cutie!