Kris is the SOUL - clarifications and FAQ
It seems the reading that the soul is, in fact, the same as Kris, is difficult for many people to wrap their head around, so here is the same take written in perhaps a clearer if less flowery manner.
♥ THE BASICS
Kris = body (vessel) + SOUL
"Body" and "vessel" are synonyms. Every lightner has a "vessel" except for ghosts, who have to find theirs. That's how vessel was used in Undertale!
The body has, much like Pink's body, its own wants and needs - just like yours and mine. My will does not want to consume the whole pie at once, but I'm gonna do it anyway. Kris is only human.
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♥ WHAT EXACTLY IS THE PLAYER?
Player = SOUL = Kris's "will and compassion", but also
Player = Kris = the only human in the (singleplayer) game
All of these are more or less synonymous: • Kris is human • Kris has a human soul • Kris is the player character • Kris is the player • Kris has determination (the power to determine fate) even in the light world • Kris can choose different paths in the story (unlike every other character) and SAVE
When you (the player) are given a choice menu, the different choices are all things that Kris could choose, or is considering, and the process of you choosing one of them is their decision-making, faciliated by the soul.
The soul is probably not only will and compassion. This line comes from the library book which itself claims that the true purpose of the soul is still unknown, and from Ralsei who, although they tend not to lie, consistently hides any uncomfortable facts from us. While "purpose uknown" could simply mean "to determine fate of the world", as Ralsei says, I wouldn't be surprised if the soul is both compassion and cruelty, or some other dual nature like that.
You and Kris are the same, because you share the same SOUL, and the soul is "the culmination of a human's being", but you are not the same kind of person because your body also defines you.
It's the same sort of situation as Asriel and Flowey - same person, different person. In fact Flowey is called the vessel by Alphys.
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♥ THE PLAYER IS IN CONFLICT WITH KRIS
This is still true. It's a conflict with you and at the same time a conflict with themself.
Kris has contradicting emotions, goals, wants, needs, obligations etc., and some of those are you while others are not. When Kris violently resists your influence, that is some other motive force (emotions, desires, obedience etc) fighting their will (you).
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♥ WHO IS CULPABLE?
Both Kris and you. Kris=soul does not reduce the player's culpability one bit.
Culpability comes from will, and you are the same as Kris's will. When you decide to put the ring on Noelle, or tell Ralsei to suck it up, that is at the same time you and Kris deciding to do so.
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♥ ARE YOU IN CONTROL?
Sometimes. You (the will) only get to choose when Kris considers multiple options. When Kris acts on their own or refuses to commit to your choices: • Kris only sees one choice • Kris acts impulsively so you don't get a say • Kris decides with their will, but another impulse interferes - painful memories, regret, conscience, obedience etc.
This is also when they rip out their soul - the need to do so is stronger than you.
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♥ WHAT ABOUT WHEN KRIS DID <blank>?
Literally all of these instances work the same exact way.
There is some part of Kris that wants X, and another part that actively resists it. You can, in fact, keep 90% of your preconceptions from a possession viewpoint, but reframe the external "possessor" as Kris's own self (which they still hate).
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♥ WHAT HAPPENS WHEN KRIS RIPS OUT THEIR SOUL
Kris gets rid of their "will and compassion" and their humanity, which is part of themself. Without the human soul, they are no longer human and hence no longer you. Because Kris no longer has will/determination, they are no longer the player character, and no longer under your (and also their own will's) control.
Kris becomes like every other NPC in the game, they don't have the power to "determine fate", which is why soulless Kris's actions are predetermined by the plot.
This is somewhat like people compartmentalizing in real life, especially when doing something morally wrong. "I had to" "I was following orders" "I couldn't help myself" People choose not to choose, to rid themself of will and therefore of guilt and regret.
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♥WHAT ABOUT WHEN KRIS KNOWS SOMETHING ONLY WE DO?
They really don't. The game very diligently never gives us opportunity to do anything that'd require knowledge of Undertale, or any other knowledge Kris has no access to. The closest exception is codes and musical notes - which Kris could conceivably already know.
Interactions with Sans are mentioned as evidence, but remember Kris and Sans are two known pranksters. One of them quite literally hits the bar for the first time and goes how about the usual. Kris also obviously does know Sans - from Deltarune. Don't discount so easily, that time in Deltarune doesn't work quite as expected. Remember, they have SAVEd before.
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♥ DOES KRIS HAVE <insert mental condition>?
If you want them to.
Kris is mentally unwell. Many mental disorders involve losing control over yourself, and Kris's situation is a good parallel to all of them. I've seen people read Kris as having OCD, DID, clinical depression; I myself have ADHD and a few other things and also massively relate to them.
I don't think any of these readings are more or less valid than any other. This is, ultimately, magical realism, and can be read many ways.
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♥ WHAT ABOUT WEIRD ROUTE?
Weird route is all about reliving Kris and Noelle's weird fucked up childhood fantasy, following their suicidal longings and pretending (~realizing) the world is all just a game.
You, the player, have no connection to Noelle and don't feel Kris's existential anguish. The weird route is even more personal to Kris.
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♥WHAT ABOUT THE META COMMENTARY?
This is all meta commentary. Kris is a player character battling the implications and consequences of being a player character. It works so well precisely because everyone else is an NPC. Kris's player-agency determines the fate of the world, and yet it's almost completely powerless in the face of the almighty narrative. Because Kris - and you - are just playing a game, and the ending came from Toby's fever dream before you were even a person.
Undertale was about how much your choices matter. Deltarune is about how much they don't.
It's all Krises, from the bottom to the top. You play as Kris in Deltarune, Kris as blue Kris in TV World, blue Kris as HERO_SWORD in Mantle, and yet despite being this ladder-entity, like the stacked Bloxer whose legs attain independence, all the power this ever gives you, is the insight to know that you were your own puppet all along. You don't get to choose who you are, and who you are, is your own abusive boss.
If you learned you were someone else's player character all along, would that make your actions any less yours?
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♥ IS THIS TRUE?
I'm not a psychic, I don't know what Toby's planning.
Neither do you. Nobody does. I have a lot of confidence in this reading, but I could be wrong.
Even then, I don't think possession will be it - much sooner it's something else entirely. Very likely we're going to get an ambiguous conclusion - Undertale sure is vague about who is who between you, Frisk and Chara.
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♥ SO WHY WOULD I CARE?
Because it makes Kris into one of the most complex video game characters of all time.
TRY IT!
Take the most absurd situation, that you think could not ever possibly work if the soul is Kris, and ask yourself - what if it is true? What does this tell you about Kris? What sort of person would ever do such a thing? And you'll find, time after time, that real life already provides examples. With every question asked Kris will get more complex.
Even if this reading is wrong, I still think it's worth taking seriously, because it makes the narrative so much more beautiful!
[index]
Ok, but then why Ralsei and Kris talk about something while we are watching Susie? And how the hell did they see past solid wall to help Susie with a Puzzle (unless narrative would omit symbols Susie telling symbols but I think Toby would not do that)? And can Kris just read thought of other people (Like Noelle tested on Weird Route)?
Also, don't forget about bit in chapter 3 where Susie mentions that Kris is controlling "her" and Ralsei briefly looks at 4th wall and then realities that she meant with Tenna gamepads.
Of course game isn't finished and we may get further evidence of this theory and it a cool narrative, but I'm not so sure that it fits with facts told by the game after thinking about it a bit.
As usual, this is only a contradiction if you already assume possession to be true.
Of course there is a player.
Susie says Kris is controlling her and Ralsei looks at the screen. Which is where this... Kris is to be found? How exactly does this tell you the player is a separate entity?
Ralsei uses "Kris" and "you" interchangeably. So does narration. So does every character in the game, including ones you'd expect to know about the player. I've even found a place where English narration uses "your SOUL" but Japanese uses "Kris"!
「クリスのタマシイ」 - Kris's soul.
The entirety of Undertale equated a person with their soul, to the point people could be resurrected from their soul alone. Deltarune literally tells you what a soul is - twice, from different sources. Kris's body is the exception for having any autonomy, and I'd sooner expect it to be the "foreign" element, except the moral of Pink was that both are equally important.
Possession is blatantly going against text, but people find it more palatable to ignore said text because they're not ready for the amount of abstract thinking Deltarune requires. Which is understandable, but that's not the same as "evidence"!