(pending rewrites)
Isn't it odd, how Player didn't speak for such a long time in Kingdom Hearts χ? It took almost fifteen months for them to speak their first words during Ephemera's introduction.
But, while its easy to say its because Player is supposed to be a silent protagonist, that gets less and less true as the game went on.
Player has quite the speech during Quest 555, or Quest 979, for example. Player certainly has things to say, and certainly makes choices beyond what we, the audience, would choose for ourselves.
So then, why is Player so quiet, especially at first?
Well, Kingdom Hearts has an example of this before.
Xion.
I don't think Player had a heart, before Quest 362. More than that, I don't think they were a nobody, since the timeline on that makes no sense.
I think Player is a replica.
First off though, lets break down why I believe Player doesn't have a heart for a second.
The first time Player speaks, its to Ephemera. But what I haven't mentioned is that Player has interacted with keyblade wielders before that.
Right before that, in fact, by the standard of KHUX. In Quest 231, Player has a short interaction with another set of wielders, where they don't talk at all.
The only unusual thing about this questline at first is they find out about the heartless from another Keyblade wielder. They all promise to meet up, afterwards. The quest goes about standard from there with Player hunting some new heartless, the other fighting heartless elsewhere.
But, unfortunately, they don't make it back.
(They certainly have a bad history with 'promises.')
This is both Player's first new connection, and their first contact with loss. I think this, along with all of their other adventures (Olympus in particular we'll be getting back to), was the inciting incident for their heart coming into life.
As Ansem the Wise said, "The heart has always been quick to grow. Each exposure to light, to the natural world, to other people, shapes this most malleable part inside of us." This is true of nobodies, but its even faster in replicas.
So if Player's a replica, why are they a replica? Who made them?
Easy.
If you are going to tell me Master of Master's wouldn't make replicas, I don't know what to say.
And he clearly he has some capabilities. looking at Chirithy.
But then, wouldn't every wielder be a replica then? Well, I don't know about that. For one thing, we clearly have some families in the wielders, looking Laurium and Strelitzia. While its certainly a compelling line of thought, it doesn't exactly hold water.
No, I think Master of Masters made only the one replica.
Player... and in doing so, sowed the seeds for the Nightmare Chirithy.
So, Master of Masters, when it comes to gaslighting and manipulating his students, truly leaves nothing to chance. He leaves lots of other things to chance, but not that.
So when he told everyone there was a ~nightmare Chirithy~, surely he'd already set that into motion.
But, as far as we can tell, when wielders go dark, most of them don't get a Nightmare, they fall. And, disappear immediately after.
So there's only the one Nightmare Chirithy: ours.
And they have a connection to the Foretellers, that never really got expanded upon.
But then, how did Master of Masters guarentee that we'd gain a Nightmare?
Well, Player explored the worlds, was exposed to people, light... and darkness. Olympus, and its darkness, also happens before we meet Ephemera, and we develop our heart.
Darkness is as much a part of our heart as any modern character. And thus, we have Nightmares.
....that said, I think that's the extent of his manipulations on Player.
The Book of Prophecies, very clearly, doesn't write down everything, and I'm not sure Luxu ever really heard about Player in detail.
For Luxu, our story is that of a background NPC. Player's choices, and their refusal of fate, goes unwritten.
The way the story ends for Player is different than the Book, because Master of Master's never foresaw their bonds.
So everything changed.
Except that, well, Player is still a replica.
I have no idea what effect this will have on the future of the games, but the subtext and foreshadowing is so clear I'm not sure why I've never read this theory from others before!
Anyways, replica!player forever! Have a good day!