The end of the second chapter pushes me to talk about this. We see Kris create a fountain of darkness. With his knife. But it's not the first time it's happened.
Kris seems to remove his heart and use his knife. And for the moment, it only happens in the normal world, let's say the Light World? Could Kris therefore be the Knight to whom so many characters refer? It's possible.
Does he do it himself or is he possessed? The fact that he is the only human in this world (does a third world with humanity therefore exist?) must be important, right?
In any case, what is the Knight's purpose? To destroy the world? Make darkness reign over the world so that the titans Ralsei talks about come back to destroy it?
W.D. Gaster is, or was, the first Royal Scientist under Asgore in the Undertale universe. He was tasked with finding a means of freeing the monsters from the Underground. He was behind several creations including the Core Geothermal Generator that provides the monster capital of New Home with electricity. He disappeared one day after one of his experiments went awry.
He found the Darkness Beyond Timelines, and it was dark, darker, yet darker... He soon discovered that he could create a world of his own, but not directly, he needed help. Gaster used a piece of his consciousness to create an entity that could take the imaginations of those who were drawn into this realm. It could then use these thoughts and dreams to give its world shape and purpose. A world that was both real and fantasy, a dark world.
Unfortunately, Gaster's creation became too obsessed with giving itself meaning. It would cause all of his test subjects to eventually breakdown, lose all sense of reality. One after another they all became lost in their dark fantasy, until they had no more dreams to give. They became "goners", forgotten beings with no place to call home. Sadly, this was also the fate of Gaster himself.
So now that the backstory and MatPat levels of conspiracy theory are out of the way, let's get into Deltarune itself.
The Man is a mysterious character that can be encountered multiple times in Deltarune. He is always hidden from the player's view, making his appearance completely unknown.
He does not have any direct dialogue; instead, every interaction with him is described through the narration. The tree the Man hides behind is similar to the red-leaved trees that populate the Field and Forest in Chapter 1.
The narration only gives very brief and mundane description of the Man. He offers Eggs to Kris for unknown reasons. He does, however, seem friendly to them, as he is once described as "waving happily to [them]."
The Man is able to travel through both the Light World and the Dark World, but whether that means he is a Lightner is unknown.
So there's obviously a lot weird with Ralsei. He starts Chapter 1 knowing Kris and Susie's names, which he obviously shouldn't know.
But there are also a few notes in Chapter 2 specifically that point to his not being a Darkener at all.
He's able to move between unconnected Dark Worlds without being transplanted by a Lightener. Both Rouxls Kaard and Lancer needed to be explicitly carried in your inventory to move between Dark Worlds at all, and they couldn't survive, even after being successfully transplanted to castle town. Ralsei, though, just shows up behind you. In fact, he came from a room that was a dead-end, except for its connection to the light world.
The only way we know it's possible to come from the closet to the library dark world is exactly how Kris did: by leaving, walking through the light world, and jumping back in. Darkeners can't do that, but it seems like Ralsei can.
There's a lot about Ralsei that's super suspicious, really.
Ralsei's Dark world is incredibly small compared to the others, and it grows in size each time another fountain is opened and subsequently closed. Ralsei talks about the importance of balance between dark and light, but after each chapter, his domain grows. And it's not a zero-sum game, either; dark worlds are created between chapters.
And Ralsei's whole motivation is allegedly acting on this ancient prophesy about the delta warriors, which no one but Ralsei has ever heard of, and whose symbols are only scattered around Ralsei's own dark world, and which doesn't have any conceivable source.
The only way we know it's possible to come from the closet to the library dark world is exactly how Kris did: by leaving, walking through the light world, and jumping back in. Darkeners can't do that, but it seems like Ralsei can.
There's a lot about Ralsei that's super suspicious, really.
Ralsei's Dark world is incredibly small compared to the others, and it grows in size each time another fountain is opened and subsequently closed. Ralsei talks about the importance of balance between dark and light, but after each chapter, his domain grows.
And it's not a zero-sum game, either; dark worlds are created between chapters.
And Ralsei's whole motivation is allegedly acting on this ancient prophesy about the delta warriors, which no one but Ralsei has ever heard of, and whose symbols are only scattered around Ralsei's own dark world, and which doesn't have any conceivable source.
Another odd thing about Ralsei's dark world is the lack of anything that corresponds with a real-world item. Everything in the card Dark World is distinctly game themed, everything in the library dark world is distinctly computer themed,
but Ralsei's world (with the Castle town, and the cliffs, and the tar eyes, and the bubble piles) is... just dark. There isn't any chalk, there aren't even the papers we saw in the cutscene.
After the secret boss fight, Kris has a panic attack about what Spamton said about puppets on strings. Ralsei jumps in to comfort Kris, but almost too aggressively, given that Kris is reacting to what is possibly a serious existential danger. It's comfort, but it's not healthy comfort.
And then there's the tea. In Chapter 2, you can get tea items themed after different characters. Each character has a different reaction (and recovery amounts) for each flavor of tea.1 Ralsei tea, though, is odd.
Kris doesn't react to any tea flavors. Noelle says Ralsei flavored tea is an empty cup. Ralsei calls it water, i.e. tea brewed without any leaves.
So, pre-chapter one, Deltarune presents itself as this SURVEY_PROGRAM (directed by W.D. Gaster) that starts with you creating a "VESSEL" character.
There are the usual options (head, body, legs) and some personality choices, but then the whole character creation conceit is subverted by your vessel being discarded and your controlling Kris instead, who is not the character you made.
Let's quickly acknowledge that Kris looks a lot like a more-colourful version of a character you could make with this screen, and then move our focus back to the survey.
I'm going to call it the Gonermaker, because that's what the game's files call it. Now, that's an interesting name. Goners are an idea from Undertale.
They're all grey, somehow-deformed versions of normal monsters. They show up with certain fun values, and only very briefly. The first three are explicitly g_followers that tell you stories about W.D. Gaster by name.
Clam Girl talks about her neighbour "Suzy" that you didn't meet, and Monster Kid talks about not existing — a parallel to the Gaster story.
(There's one other object that has a recolored grey version, and that's Sans' door/warp door/mysteryman door. That's not directly related to this theory, but it is noteworthy.)
In the Gonermaker, you are making a goner. You are "connected", your answers (your "feedback", if you will) is collected, and you construct a grey, deformed version of Kris.
In addition to their hair and body features not matching up, they notably do not have a mouth.
So, what does that mean? Well, Goners are goners of other things. There's a direct relationship there. So, Kris is to [your vessel] as monster kid is to goner kid, whatever that means.
Here's a thought; what if we use the Gonermaker information to inform the Goners in Undertale? Perhaps all Goners are Vessels. Ours was "discarded", but the Goners in Undertale seem... well, not present, but certainly more present than Goner Kris.
Are they successful products of the survey program?
Anyway, when I started writing this, I was hoping it would inform why Kris is Doing Weird Stuff, but I kinda hit a dead end there.
I thought maybe Kris was themself a vessel for something, but it doesn't seem like they are. Maybe our SOUL would "fit better" in a Goner, without the Kris/SOUL conflict we see in Deltarune?