WMG / Deltarune The Heroes

Susie

Susie has Abusive Parents

If her parents were cruel to her, it would explain why she is a bully and didn't trust anyone at the start of the game.

• When you meet Susie and Lancer eating the salsa, Susie mentions how she only had chalk for breakfast. Have her parents been feeding her at all?
• In Chapter 2, while deciding to stay at Kris' house, Susie doesn't call her parents when told to.

Suzy is Susie's sister, or at least a family member

Catty and Catti are two sisters with extremely similar names, maybe this is also the case for Susie and Suzy?

Susie is the Purple Guy's daughter

More of a joke WMG based on the meme about her being Barney the Dinosaur's daughter.

When talking to Burgerpants, he claims that there's a "purple guy" whom he's not sure works at Ice-E's or not. While most people would think it's a shout-out to Five Nights at Freddy's, we do see a purple dinosaur monster with an Ice-E mask outside the restaurant, working. Considering we don't see any other purple dinosaur monsters in the game other than Susie and him, it's safe to assume that the "purple guy" is her dad.

This explains her behavior. She's ashamed that her dad works as a pizzeria clown, so she puts up a really mean persona.

Susie and Suzy (mentioned by Clam Girl in Undertale) are two different characters/alternate versions of each other

Likewise, Kris could also have an alternate version of themself named Chris (who could look similar to Chara in Frisk's clothes).

Susie comes from an abusive or neglectful household.

Ragged-up clothes, troubled behavior and bullying, obvious enough — but she also eats chalk, devours the cake at first glance, and often complains about hunger and not being given food. It's fairly obvious she doesn't get enough to eat at home.

• Her comment about Kris having "a good mother" that didn't deserve to bury her child (as an excuse to not bite their face off) does have some implications that Susie herself does not have one.
  • Reinforced by the_n3w3st_g1rl_g1rl, in which Susie gives Kris a rant about how their mom might get sick of them that can easily be seen as Psychological Projection. Kris' unheard Armor-Piercing Response might even be an accusation thereof.
• If you talk to Lancer after defeating the King, Susie approves of the changes he says he's making, one of which is "Prison is now only for dads!"
  • Susie has an amazingly scary face; imagine what her full-grown, adult monster parents look like. What if she gets along with Lancer because she's all too familiar with what it's like to have a scary dad?
• In Chapter 2's epilogue, while staying at Kris' house, she does not call her own parents after she was told to.

Susie is from the world of Undertale, who has unknowingly become stranded in the world of Deltarune, and her mother is the Queen

Susie is the only major character whose clear counterpart to an Undertale character is… complicated. As referenced elsewhere in the page, a "Suzy" and her parent(s?) are referenced by a Gaster follower in Undertale, but nothing remains of any "Suzy" to interact with in the game's code. Susie in Deltarune is a character seemingly without place; while your classmates have their families and the Undertale cast is more-or-less firmly rooted in the community, there isn't any clear home for Susie in Hometown, and no clear family members either. The only other characters unaccounted-for-but-referenced are the town's mayor, an unnamed and unseen woman, and the Queen and Knight from the Card Kingdom, who have a villainous but as-of-now enigmatic role in the game's plot.

If Susie, by some circumstance or another, is in fact the same "Suzy" we see referenced in Undertale, then her societal place and general behavior (noted by some players as being characteristic of a toxic household) would seem to hint that this happened before she was old enough to know what was going on, and probably lives with the mayor/Queen analogue, who has treated her poorly.

This may also be foreshadowed by Lancer's relationship with his own father, as a rough bad guy who's ultimately willing to change has to overcome his relationship with a nakedly selfish tyrant.

• Partially jossed, as Queen has been introduced and she is most definitely not Susie's mother, while the Mayor was confirmed to be Noelle's mother. The rest of the theory is still up in the air.

We will get to play as Susie

At one point, our viewpoint leaves Kris and we get to watch Susie; although we don’t get to control her or anything, this could be potential foreshadowing that we will eventually go over to her. The ending makes this more likely, given that after being locked in a birdcage and finding out Kris is possibly a knife-wielding maniac, we/the soul may decide to jump ship and go over to Susie, at least temporarily (since I do also think that we may get to control the vessel we made eventually).

Susie is suicidal to some degree.

At least in one puzzle sequence, she plans to impale herself over a fence.

Suzy is to Susie what Frisk is to Kris.

Whatever the relation between Frisk and Kris is, the one between Suzy and Susie will turn out to be the same.

Susie's ability to heal will become stronger over the chapters, especially with both repeated use and when used on herself.

It just makes some amount of gameplay sense for the Gang's primary source of damage output to have some ability to sustain herself.

It might also become a Chekhov's Gun

• It could also be used as symbolism for her character development; the shinier her heart of gold becomes, the stronger her healing will become. Or a major step forward in her character development will coincide with her figuring out how to properly cast Ultimate Heal.

Susie is homeless.

In addition to arguments others have listed for her having neglectful/absent parents:

• She's drinking the milk Alphys leaves in the alley.
• She fantasizes about bringing Darkners to their world, she says Lancer could live under Kris' bed, but doesn't mention her own bed despite being the one who gets along best with Lancer.
• She's pleasantly surprised, but also somewhat confused, to have her own room. The way the dialogue is written, "her own room" might a room that belongs to her at all, rather than a room to herself.
• During one of the Queen's spotlight puzzles, Susie's purple spotlight is in the shape of a house.
• One of the searches from her room in Queen's castle was made from the library computer. Susie doesn't exactly seem like the type to go to the library if she had anywhere else to go.

Susie came to Hometown only after Asriel left for college.

Her dialouge when looking in Asriel's room in Queen's castle suggests that Susie has never met Asriel before, despite most other Hometown citizens knowing him and having a high opinion of him. She's known Kris for some period of time and holds Toriel in high regards at the beginning of Chapter 1, so it's possible Susie only came to Hometown after Asriel moved and the two never formally met, thus she only knows of him through word of mouth.

Susie is Aromantic.

She's completely unaware of anyone else's feelings for her, even if the player has Kris confess directly to her face. Her extensive Ship Teasing with Kris and Noelle will be used for meta commentary about Shipping, such as the entitlement in assuming Kris (and by proxy, the player) can get with her just because they're the player character, or thinking she has some sort of moral obligation to date Noelle, even if she can't like her like that or she realizes it wouldn't be a healthy relationship because Noelle's feelings are ultimately highly surface level, just because uninvolved third parties think they're cute together.

Of course, huge swathes of the fandom will completely miss all this and decide that Toby is just a homophobe.

• Given the subtle implications that Noelle's feelings are slowly becoming mutual (such as her akward attempt at inviting Noelle to hang out that got interupted by Berdly, or randomly thinking of Noelle while examining Ralsei's dummy or baking with Toriel), it's likely that Susie's just absolutely dense when it comes to romance.

Ralsei

Ralsei is Asriel

Just as the Lightners, Noelle, and Berdly appear in the Dark World in their dreams, so too does Kris' elder sibling. Makes it rather adorable that Kris couldn't do anything or go on a single adventure by themselves without Asriel being by their side in some shape or form. Also heartwarming that even in college when he's supposed to be studying, he's never too busy or too old to play pretend with his beloved younger sibling.

• Another piece of evidence, if Ralsei is truly a Darkner, then why didn't he petrify in the Cyber World?
  • Ralsei explained that his fountain is pure darkness, hence why any Darkner can live in the Castle Town regardless of where they're from. Since he was born from that very same fountain, it isn't much of a stretch to assume that the opposite is true and that he can exist in any other Dark World no matter where it's located.
• Ralsei's way too young to be Asriel. We know Asriel is in college, while Ralsei is around Kris' age from how he looks like.

Ralsei is the key to saving Flowey.

Related to the two WMGs above, if the Deltarune timeline has two iterations of Asriel's SOUL, while the Undertale timeline currently has none… You can probably imagine the rest, but basically, if the Alters were ever to encounter, it is more than just likely that Ralsei and his kind heart may choose to perform a Heroic Sacrifice and merge with Flowey in order to give his least fortunate Alter a happy ending.

• Considering how beloved Ralsei has become in the fandom, I’m pretty sure if this was the case, the entire internet would revolt.

Ralsei (Asriel?) got all the wrong heroes.

The prophecy states that "a human, a monster, and a prince from the dark" will save the world. Ralsei assumed this was Kris, Susie, and himself. But "a prince from the dark" would also describe Lancer, and Kris doesn't seem to be in any position to be a hero at the end of Chapter 1. Maybe the final party will consist of Lancer and a different human and monster. (Alternatively, Ralsei could be the monster, rather than the prince.)

• In addition to this, Ralsei is a prince with no subjects. He doesn't exactly have much in the way of royal responsibilities.

Ralsei isn't one of the heroes from the legend.

The Darkners do not appear to be the same thing as monsters, and everyone in the Darkner kingdom has either a playing card or checker motif. But Ralsei does seem to be a monster, being an Identical Stranger to Asriel with a Significant Anagram name, and lacks any visual connection to the realm. This is because Ralsei is only pretending to be a Darkner, and therefore can't actually be one of the three heroes. Ralsei isn't even a prince since he has no subjects, though he doesn't seem to be a bad guy. Like Alphys in Undertale, he wants to be a hero, but his attempts almost end in disaster when he's Wrong Genre Savvy and heals the King. The hero of legend he claims to be is a Darkner Prince, and Ralsei isn't either of those things. Like in gameplay, he's just ACTing. Lancer, on the other hand…

• While it is possible Ralsei isn’t one of the three heroes, one thing that a few people noticed is that the Darkners have colored portraits during their dialogue while Lightners only have purely white and black. So I think this is an indication that Ralsei is actually a Darkner, even if he isn’t part of the prophecy.
  • Fair, and the colored portraits = Darkner idea definitely seems like it's intentional. But Toby Fox is exactly the kind of creator who would use the medium itself to maintain the deception until it’s revealed to the player. Whether or not it's actually true, Ralsei is being presented as a Darkner, so it makes sense that his portrait would have color. I don’t find it implausible that Ralsei would switch to a black and white portrait upon being revealed as a Lightner if he actually is one.

Related to the above: Ralsei is aware that he is not the third hero

He is putting on the act of being the third hero because he is a lonely kid who desperately wants to have friends. The prophecy guaranteed him that he would meet two compatriots.

Ralsei will be turned into a plant at some point, and Lancer will replace him as the Prince From The Dark in the Prophecy

This will either be temporarily or permanently, and will harken back to Asriel being transformed into a flower in Undertale; note how Ralsei is the only major character that really uses green in their color scheme, much like how Asriel was the only important character in Undertale with a green color scheme (and note that Flowey and Asriel use the exact same colors, the green from Asriel's shirt being the flower's stem, the yellow stripes translating to the petals, and the white fur becoming Flowey's face, so perhaps Ralsei could do the same, becoming a pink flower of some kind, like a rose, incorporating Ralsei's horns, pointy hat, and scarf as the thorns). In the time while Ralsei is taken out of the picture from his new floral transformation, Lancer will take up his role, both in-universe as the Prince From The Dark, and mechanically as the party's spellcaster, this time with a focus on offensive magic and status effects (such as fire, like how he lit his bike ablaze, or paralysis, like how King's attacks focus on limiting the player's movement).

Ralsei represents what Kris wishes they could be above all else: a full-blooded Dreemurr.

When Kris was younger, they didn't understand why they didn't have horns, fur, or magic like the rest of their family. Toriel got them a headband which they used to wear all the time, until they outgrew them and came to accept that they were 'just a human'…

…except that Kris hasn't fully made peace with that. Deep down, part of them still wishes that they could have been part of their family by blood, rather than adopted. And Ralsei is a reflection of that — a manifestation of what they wish they could have been born as. What they would have chosen to be, if given the chance.
Their horns are red because of the headband. Their name's a rearranged version of Asriel's because Kris envisions their ideal self as a younger version of their beloved brother. His adorkable nature and idealism all reflect what Kris believes a better version of themself might be like… as well as how Kris might have been when they were younger, before they forced themself to accept that they'd never become what they really wanted to be.

They couldn't choose who they are in this world. They couldn't tailor their body the way they wished. That form only existed within their own imagination…

• Ralsei's Pacify spell and status as the White Mage reflect how Kris wishes they could magically heal the rifts that have formed in their family. There's likely a lot of Tension in the Dreemurr household, and the thought that they could turn that Tension into fuel for some kind of spell that could instantly mend old wounds manifests into Ralsei's skillset.

• Ralsei's name being an anagram of Asriel's is because Asgore's bad at naming, and 'Ralsei' is most likely what Kris would've been named, but Asgore asked Rudy instead, who suggested 'Kris' (complete with the Holiday theme, because “Kris-mas” or “Kris Kringle”). Ralsei's most likely Light World item is Kris' old horn headband they wore to fit in with the Dreemurrs, explaining why they're Kris' dream self in the first place. Ralsei is also compatible with every Dark World because he wasn't made for a specific location, he's a clothing item! That would mean he's always with Kris because he's their accessory! (Also, now that I think about it, that could explain the "I'm with you in the dark" line from the credits song. Did Ralsei write those lyrics for Kris?)

Ralsei's similarities to Asriel are a red herring.

Asriel is mentioned by several characters in the Light world, but is conveniently away at university and therefore never seen. Upcoming chapters will increasingly suggest the idea that Ralsei is Asriel, perhaps implying that Susie's reaction to seeing him take his hat off is because he looks just like Asriel. But it will later be revealed that he either genuinely is an Identical Stranger whose resemblance to Asriel is solely meant to mislead players from a meta perspective, or that his Boss Monster-esque appearance is not his true one and for some reason he's decided (or been made) to take that form instead.

Ralsei doesn't actually look like Asriel — it is all an illusion

Notice how when Ralsei reveals his face, he holds his hat over face for quite some time before pulling it away, as if he is trying to get ready for something, and when he pulls it away, this action is accompanied by a sound-effect? That is him, as mage, casting some sort of illusion spell on himself, to give himself Asriel's appearance. It would explain why so many details about his unmasked face are off when compared to his normally masked appearence.

If Ralsei's unmasked appearence is an illusion, he is not intentionally making himself look like Asriel

Related to the above theory, Ralsei's illusion spell doesn't specifically make him look like Asriel. It merely gives him the appearence of someone the person(s) looking at him trusts, or otherwise holds in high regard. Asriel is frequently made out to be a highly beloved member of Kris and Susie's local community of Hometown, and has a personal connection to Kris to boot, so it would make sense that he takes on his appearance in their eyes.

• It's possible to take this even further. Maybe the Ralsei Susie saw doesn't look like Asriel at all, but like someone she knows and trusts. If that person is dead or otherwise unreachable, it explains her shocked reaction when Ralsei takes off his hat.
• Even more fuel to this fire. When Noelle see Ralsei in chapter 2, she says "That looks like..." but never finishes that thought. The player is probably expecting her to say Asriel… but what if it's someone else? Noelle's own absent sibling, perhaps?
  • Chapter 2's epilogue puts this theory into doubt. Susie explicitly points out Ralsei's resemblance to Toriel if you express doubt about him and Lancer visiting the Light World. She also didn't know that Kris had a brother, which means she doesn't know who Asriel is or what he even looks like.

Ralsei will pull a Face–Heel Turn

Considering what his name anagrams to and the character arc of said character in Undertale, and how this Else World seems to be playing with what we'd expect from the characters in Undertale, it seems reasonable that Ralsei's character arc will be the inverse of Asriel/Flowey's. There's already parallels in the first chapter.

• Asriel/Flowey's earliest words to the player are that the world is 'kill or be killed'.
• Ralsei's earliest words are how 'nobody has to die in this world'.
• Flowey spends most the game being a violent sociopath until the Golden Ending where the SOULs of the six children and all the monsters in the mountain, albeit briefly, manages to repair his SOUL back to being Asriel and allows him to remember how he used to be a good person.
• Ralsei spends most of the game advocating a pacifistic approach to the adventure until the end of Chapter 1 where, after being tricked by the Spade King, begins to ponder if violence really is needed in this world.

As such, it could be concluded that Ralsei was originally a violent sociopath until something damaged his SOUL, leaving him to take a pacifistic approach/unwilling to conduct any violence. At the climax of the story, Ralsei's SOUL will be "repaired"… At which point he'll become a violent sociopath again, forcing the remaining two heroes to fight him.

• If this is true, Lancer's words in Chapter 1 would be an ironic future lampshading. If you picked Susie's team name, Ralsei would disagree, and Lancer commenting they should swap roles (Lancer being good guy, and Ralsei as villain).

Ralsei is a Darkner as he claims… specifically, the Darkner counterpart of the red devil horns headband Kris used to own and at some point lost.

Toriel mentions that they bought the headband because Kris kept asking when their horns would grow in, and that sentiment left behind is why Ralsei takes form as a Boss Monster. Ralsei's horns, at least in the non-portrait sprite go inwards, similar to a traditional pair of devil horns, and Ralsei's unique equip dialogue for the Jevilstail item is "I'm a good devil, OK?". Additionally, one might be able to argue that Ralsei's 'worship' of the Lightners, as King puts it, is as a result of Kris supposedly loving the headband so much that they wore it for months on end, and from all sounds may have genuinely lost it as opposed to being 'abandoned' like the items in the empty classroom. Considering that most Darkners that appear in Chapter 1 are based on children's toys, it seems definitely within the realm of possibility.

The River Person in Undertale is actually Ralsei, who found his way in the timeline somehow.

The cloak that he wears during his introduction before Lancer knocks him aside greatly resembles of that of River Person.

Ralsei will say "That Man Is Dead" in regards to Asriel

There could be a lot of reasons he could say that. Maybe he could have succumbed to the pressure of being Asriel and adapted a new persona, or maybe he just wanted to start a new life.

Ralsei will inexplicably appear in the Hometown and greet Kris and Susie.

Susie's reaction will be to casually greet back, before realizing who just showed up in a Double Take.

Ralsei is a representation of who Kris thinks Asriel has become.

Asriel was the same as in Undertale — a sweet crybaby who wouldn't hurt a fly. However, as he didn't die as a 8-year old, Asriel grew up, stopped being childish, slowly distanced himself from Kris, and eventually went to college: Kris thought Asriel betrayed him, especially since they had a rough time as Toriel and Asgore divorced recently.

Ralsei's role in the story is Kris' interpretation of who Asriel is: Originally a heroic cinnamon ball who is just so sweet, but slowly becomes meaner until he completely betrays the Fun Gang. The Pre-Betrayal Ralsei won't have any negative qualities Childish-Asriel had, and won't have any redeeming qualities after his betrayal: Kris, in a fit of rage, sadness, and betrayal, crossed them out of their mind.

At the end of the week, Asriel returns. And then, two things can happen:

• Option 1: Asriel is the same, nice person Kris remembered him as, except less childish.
• Option 2: Asriel has changed a lot for the past few years, breaking Kris even further.

After this, one of the two can happen:

• Option 1: Kris realises they were too childish and stupid. Ralsei either pulls a Heel–Face Turn and helps the Fun Gang defeat the real villain, or Kris kills Ralsei as they want to forget how stupid they were, get over it and grow up, just like Asriel did.
• Option 2: Kris is even more heartbroken. Ralsei becomes even more cruel and heartless as Kris falls in despair: It will end with a showdown against Ralsei who will become stronger and stronger due to Kris' feelings until their friends (Susie and a few others) manage to make them calm down, and sadly accept that Asriel has changed: Ralsei will once again be killed by Kris. For bonus points, Ralsei might be the Climax Boss and/or he will cross the line at one point.

This is a part of a larger theory that might be posted one day: Deltarune will be about helping some of the characters become better people: Susie already had this in Chapter 1, and the fellow chapters will focus on other characters, with Kris being the final one.

Ralsei will have a battle theme, but it won't be in the game.

In Undertale, Sans has his own battle theme on the game's soundtrack ("Song That Might Play When You Fight Sans"), but since he isn't fought on a normal playthrough, it deliberately goes unused, with his Genocide battle theme being "MEGALOVANIA". Since Ralsei doesn't seem like the kind of character that would fight us as a boss under normal circumstances (as opposed to Susie or Lancer), perhaps he will have a battle theme that appears on the soundtrack but never plays in-game. Alternatively, if he does get a boss fight, the music will be a completely different song befitting the situation.

Both Ralsei and Lancer are heroes of the prophecy

Ralsei and Lancer wearing a pointy hat and a pointy hood respectively symbolizes how they're the two upward triangles of the Delta Rune (the Monster and the Prince). The downward triangle symbolizes the Human, or more specifically a downward-pointing human SOUL.

Ralsei will be influenced by the player.

Playing off some of the above theories about him pulling a Face–Heel Turn, perhaps that could only be one possibility. During the course of the first chapter, the player has a few opportunities to either be nice or mean to Ralsei, from hugging him during the tutorial to throwing away his manual. Maybe there will be other such opportunities scattered throughout the full game, and Ralsei's character will change depending on how the player treats him, with his mood increasing when the player is kind, and decreasing when the player is mean.

• At a high mood, Ralsei continues to be kind and compassionate, both towards his teammates and to other characters. At a high enough mood, he might even gain a boost to his magic due to how close he's gotten to you.
• When his mood is somewhere in the middle, he becomes more morose and passive, not taking initiative on a lot of things and believing that the team's journey is pointless.
• If his mood drops low, however, he ends up becoming a darker (no pun intended) and uncaring person, treating everyone around him harshly and making brazen comments. If the player has been particularly cruel to him, he might wind up doing a full-on Face–Heel Turn towards the end and becomes a bonus boss, with his magic attacks becoming incredibly powerful due to his absolute hatred of you.

Ralsei isn't real.

Ralsei might be a supportive lovable ball of fluff, but what if it's all just a lie? What if Ralsei, or the entity we know as Ralsei, doesn't actually exist and is simply just a fake created to mislead/misdirect the player and the other heroes? It might seem like a stretch, but there are a few odd details regarding him:

• For one, when we meet him, the city he's in is seemingly lifeless. There's no one else around and the buildings themselves can't be entered, almost like they're just a backdrop.
• Secondly, no one seems to recognize or know who he is. For being a supposed "Prince", no one acknowledges him as one. In fact, the only person who really calls him as such is Ralsei himself. Tying in with the empty city, his title of "Prince" seems a bit dubious.
• Following from that, he doesn't seem to completely fit in with the prophecy, with the "Monster" being taken by Susie and "Prince From the Dark" applying more to Lancer, who is explicitly shown to be a prince within the Dark World.
• And then there's the secret conversation he has with Kris when our attention is changed to Susie. Since we only hear the very end of it, it's impossible to know what he was telling Kris, and could very well have been trying to convince them to ignore/abandon the player or otherwise feed them false information.
• But perhaps the most glaring thing about him is that he's just too damn nice. With the current state of the Dark World, it seems a bit odd that someone as kindhearted as him would exist. There's also the fact that with him being so nice and helpful, both the player and the other heroes would be more likely to listen to him or believe him when he says or suggests something.

With all that being said, it's entirely possible that Ralsei is some kind of puppet created by the Knight or the Queen (or perhaps even the Angel?) in order to try and fool the heroes and/or lure them into a trap, thus subverting the prophecy.

• Queen is out of the picture.
• Noelle's reaction to "Ralsei Tea" is that there's nothing in the cup. Maybe it's because she hasn't had the chance to spend time with him, or maybe it's because she's the only one who hasn't been fooled yet.

Ralsei isn't Asriel, but he is his analog/counterpart from the Dark World.

Ralsei evidently isn't normal even by Darkner standards, since he apparently isn't bound by all the same flaws that other Darkners are, such as being prone to turning to stone when away from the area created by his Fountain. He also has knowledge of the school in the Light World and the contents of it despite never having been stated or implied that he's personally been to the Light World, but that's something that Asriel would know about, having lived there and gone to school in that same school. It could be that Ralsei is a special case in that, while other Darkners have analogs in the Light World that are inanimate objects, Ralsei's Light World analog is a living being, Asriel. This somehow affords him special abilities among Darkners, as well as some knowledge of what Asriel has experienced, and it's also why he's so fond of Kris even though the two haven't known each other for very long.

Ralsei's light world object is a pink flower.

Obviously, his scarf represents the flower's pink petals, and his robes represent its green stem. Him being a flower in the light world would not only be a good way to make a parallel to Flowey, but it would also tie back to the officially-licensed "Floralsei" t-shirt.

But why does he resemble the Dreemurrs? Well, Asgore runs a flower shop in town and likely has had an interest in flowers/gardening for a very long time, so maybe this flower had thorns and he accidentally pricked himself on it, thus imparting his likeness onto Ralsei.

That being said, I admit that I couldn't come up with a good explanation as to how this flower ended up in the school's supply closet, how and why it's still alive (I imagine it needs to be in order for Ralsei to exist), and why Ralsei's name is an anagram of Asriel's.

Ralsei's Appearance Is in the Eye of the Beholder

Explaining why Susie shows such a strong reaction to his appearance but not to Toriel's who looks similar. Ralsei is never actually called a goat or implied to be goatlike by any character. If Noelle drinks Ralsei Tea, she remarks that the cup is actually empty; maybe she seems him as invisible?

Alternatively, Ralsei is a Shapeshifter.

He hid his face and hands under his hat before he revealed his appearance. His face doesn't look white until he covers it with his hat, neither do his hands. Notably, his hands seem to be revealed as white before his face. Maybe he secretly changed his appearance while covering it with his hat.

Ralsei is loyal to the player

...As in, specifically to the player. Not to Kris. Note how the capital of his dark kingdom is named after the player. While Ralsei does speak to Kris outside the player's POV, most of what he's saying is encouraging Kris to be be loyal and obedient to the player too. This drives Kris to distrust Ralsei for the same reason they hate the player, which explains why the Ralsei Tea only heals them for 60 HP.

Ralsei absorbed a monster soul.

Spamton and Ralsei are the only darkners that display knowledge of souls and Spamton was interested in absorbing a human soul. Ralsei is the only Darkner to resemble a species of monsters. (Spamton NEO and Mettaton are both piloting physical artifacts, they don't count.) Ralsei has the ability to exist in Dark Worlds other than his own, which other Darkners don't have, which would make sense if he had a soul to animate his body, making his fountain redundant. If a soul gave him the ability to exist outside his fountain's range, it would also allow him to live after the fountain was sealed or after the Roaring, making absorbing a soul a clever move for the future. Maybe having a soul even gave him the ability to exit the dark world, explaining why we never see his object version and how he managed to get to the computer lab. (Note how he always leaves the party before Kris and Susie seal the fountain; maybe he quickly leaves the Dark World before we do so we don't see him.)

Ralsei is a special Darkner

While most Darkners are tied to a single object or a combination of objects (like Bloxer), Ralsei is special in the fact that there are not only multiple objects that represent him, but they all are able to exist independently, allowing him to exist in multiple Dark Worlds at once. This is because of Kris's desire to be a true Dreemurr being so great that they imprinted it onto many different objects. Many objects talked about in other theories all represent Ralsei, and all exist in various Dark Worlds:

• The red devil horns
• The missing green crayon
• A red scarf
• A flower
• A hat
• A pair of glasses
  • Ralsei is likely the shards of glass. Not only would this explain how he's able to see into the Light World and seemingly know what's going on in the Light World at all times, but it might explain his disappearing animation when he gets knocked out: he's literally shattering.

Ralsei is a Lightner/Darkner hybrid

It would explain some of the more… strangely suspicious aspects of him, and how he has a colored portrait like the other Darkners at the same time.

At some point, Ralsei will jokingly ask for someone's credit card number.

Bonus points if the target of the joke doesn't even have a credit card.

Ralsei is not secretly a bad person, but he struggles with a Lack of Empathy.

Either due to lacking a soul like Undertale's Flowey or mirroring a real-life condition such as Asperger's syndrome or SZPD. He might truly have had the best intentions when he tried to divert Kris' attention after the Spamton NEO fight, but he doesn't have the cognitive capacity to understand how to deal with his friends' negative emotions properly. It would also explain his dedication to extreme pacifism and why it never ocurred to him to question Susie's reasons for her attitude in Chapter 1 — he's trying to be "good" the only way he knows how.

Ralsei's form in the Light World is Kris's knife

In the manual, Ralsei gives thanks to the "Unending Pillar of Darkness that gives my body form." While he could be simply referring to his status as a Darkner, Kris using their knife to open a pillar at the end of chapter 2 makes it possible that he's referring to his status as the source of the Pillars. This also explains several things about his character. How is he able to move with Kris and Susie? Because Kris is always carrying him around, whether we see him in the inventory or not. How can he resist being turned to stone in other Dark Worlds? Because they're all created using him. Why is he so close with Kris in particular? Because Kris literally owns him. If the knife is ever revealed to be a gift from Asriel, that also explains his appearance.

• One slight hiccup in the theory is that Kris briefly leaves the Castle Town Dark World to retrieve the objects that made up the Card Kindom Dark World and bring them back, while Susie stays behind. If Kris was carrying Ralsei's Light World form with them when they left, Susie would've noticed Ralsei disappear during that time and possibly commented on it when both returned. Only possible explanation for that would be if Ralsei slipped out of sight in that time so Susie wouldn't even notice him disappearing.
• Also, why would a knife be as relentlessly committed to non-violence as Ralsei is?!

Ralsei has a Shadow Crystal.

If you use a Shadow Crystal while in the dark world, you will seemingly get a glimpse of the Light World counterpart to the Dark World you're in, seeing toys strewn about a floor in the Card Kingdom or the Librarby's Computer Lab in the Cyber World. Ralsei has some knowledge about the Light World, so they could possibly have a Shadow Crystal to look through in order to learn about it.

Ralsei doesn't represent an object at all, but rather an emotion.

After all, Chapter 2 shows that things like ads, computer viruses, and task managers can become Darkners even though they aren't physical objects, but computer programs. As for what specific emotion(s) he represents, there are multiple hypotheses:

• Love. Setting aside the obvious connection, his kindness and sympathy toward basically everyone he meets are pretty much his defining character traits.
• Kris's feelings toward Asriel. This would explain why he looks like Asriel, as well as how he was able to reach the Librarby's Dark World.

Ralsei represents a young Asriel's idea of a sibling.

While Asriel no doubt had made quite a few friends in his youth, it's possible that he felt lonely at home, being a lone child. This loneliness would've lead to him dreaming up a sibling for him to play with.

Ralsei's kind and helpful attitude might be what young Azzy wanted in a sibling: Someone as kindhearterd as he is and who would always be there to cheer him up when he was sad, help him out when he struggled, or come to his rescue if he was in trouble. As for Ralsei's name, Asriel likely takes after his father when it comes to making up names, so he simply just rearranged the letters in his own name to make a new one.

If Asriel had drawn a picture of his dream sibling, it's not unreasonable for him to have taken it to school or otherwise given it to Toriel, where it would eventually find its way inside the school's storage closet. A drawing would also explain the missing green crayon, since it could've been used to color in the clothing.

Once Kris entered Asriel's life, he would've discarded the idea, since he no longer needed to fantasize about having a sibling. This is why Ralsei is found completely alone in an empty kingdom: He was merely a child's idea of the perfect sibling and was left abandoned, with no friends or family to call his own.

Ralsei isn't omitting information for malevolent purposes, he just assumes that we already know everything, and only realizes otherwise when somebody has a Freak Out or is about to act in a way that could only be done if wildly uninformed.

Ralsei is a "Super Boss"

A common theme that the holders of the Shadow Crystals share is gaining a certain degree of fourth wall awareness after meeting a certain "someone". Perhaps Ralsei met this "someone," but didn't Go Mad from the Revelation like the bosses did, instead using his newfound meta knowledge to teach the player how to play the game.

Ralsei wants to collect every darkner in his town in order to pull a Flowey.

Ralsei tells us to recruit every darkner into his town. The recruiting manual which presumably Ralsei wrote says that something special will happen if we recruit them all. This is similar to Flowey's plan in the pacifist ending, which involves bringing all monsters in the Underground to the barrier room, so he could absorb their souls. Either he wants to absorb their souls, wants someone else to absorb their souls or wants to perform some other ritual which needs seven dark worlds worth of darkners.

Ralsei does have an ulterior motive, but not an evil one

Keeping this motive a secret from the rest of the cast will come back to bite him however.

Ralsei is the representation of Kris' envy towards Asriel.

A subtheory to the "Ralsei is Kris' memories of Asriel" theory. While it is a WMG that's most likely true, anything about that theory fits with the Undertale Asriel, not the Deltarune Asriel. Comparing the latter Asriel to Ralsei, they don't line up.

• Asriel's popularity implies he is very sociable, confident, and possibly even a Chick Magnet. Ralsei is very socially awkward, has very few friends and has some self-esteem issues.
• We don't even how much Ralsei resembles Asriel. For all we know, he resembles the Dreemurr family in general rather than Asriel specifically (Susie even says he looks like Toriel).
• They are definitely not the same age, and given the age difference, probably height too.

So, what if Ralsei is Kris manifesting their resentment of Asriel into its own person? As much as Kris loves their brother, it's been implied through their room in Castle Town he is deeply envious of how succesful, popular, competent and possibly even independent he is. In a result of Tall Poppy Syndrome, instead of trying to make themselves as good as Asriel, Kris just imagined an Asriel who is worse than them. An Asriel who is lonely, socially awkward, short, and even less independent then Kris themselves. The same way it's implied Kris needed Asriel to have a social life, Ralsei is constantly around Kris and pretty much needs them - That way, they won't ever "betray" Kris and go somewhere like college. Ralsei being such an introvert implies Kris might also be envious of how open Asriel is.

And the reason for the implications that Kris doesn't like Ralsei that much? Kris knows what Ralsei is supposed to be, and feels ashamed of it, so they act cold and distant towards Ralsei. Kris does love Asriel very, very much, and they're not proud of themselves for thinking "oh boy I wish it was him who is the loner with no friends who's dependent on someone else".

Ralsei isn't evil, but being lied to and manipulated by some other antagonist

Possibly the Knight, or whoever the Knight might be working for. This antagonist is preying on Ralsei's loneliness by feeding them as bunch of BS of how he's destined to become a hero and make heaps of friends blah blah blah, much like how Flowey strung along Papyrus. Ralsei has already shown he can be taken in pretty easily, so it's not hard to imagine this scenario, and maybe even convincing Ralsei to keep secrets from everyone else.

Ralsei's "private conversations" with Kris were instructions.

• Ralsei and Kris have been in kahoots since before the start of the game, with Ralsei being aware of the player. Kris doesn't seem to be very fond of Ralsei (if the Tea theory is anything to go by, anyway), but we also know from the blood splatter outside the wagon-cage that they've been tearing their SOUL/player's influence out of their chest since before the start of the game, too. Ralsei has convinced Kris that opening Dark Fountains is the only way to progress the story, and concluding the story is the only way to purge the Player's influence from controlling Kris. This is consistent with the Weird Route, where Kris, implied to be unusually cruel due to the Player's control, doesn't give Ralsei the chance to be alone with Kris by being distracted with what's going on with Susie.

Ralsei is Kris's old pair of horns, but is an especially unique Darkner coming from a fountain of pure darkness because of the Noodle Incident involving Kris and the Bunker.

Kris used to wear those horns everywhere when they were younger, and possibly did while they were out with their brother and friends. Something happened at the Bunker involving Kris, and they possibly went in before coming out, missing their horns but unable to explain why to everyone else due to the trauma. With the Bunker's connection to Gaster and thus Gaster's connection to darkness, it's possible who or what is in the Bunker used the object as an experiment, and cast the horns into a source of pure darkness, creating Ralsei. How it later ended up in the school's supply closet is anyone's guess, though.

Other/Multiple

A fourth character will join the party in a later chapter

Lancer is the most obviously likely candidate with Noelle being a close second, though it could always turn out to be someone else. This fourth character along with Kris, Susie, and Ralsei will complete the Balance, Power, Skill, Gimmick team.

• Partially confirmed; Noelle joins the party in Chapter 2, although only when it's just her and Kris. Once we reunite with Susie and Ralsei, Noelle leaves the party.

There will be a total of 6-8 party members

We'll get to choose 3-4 of them to fight in battles. Since Kris, Susie, and Ralsei's theme colors are light blue, purple, and green respectively, the other five members' colors will be orange, blue, yellow, red, and white to match the colors of the seven human SOULs + monster SOULs, though it's also possible that we'll never get a red or white party member because those colors are the "odd ones out".

• Berdly, Catti, and Noelle all have enough personality, plot hooks, and character flaws to be explored as major characters and invited to join in.
  • Two-thirds confirmed, one-third unclear. Noelle is the yellow, Berdly never actually joins your party but can be implied to be the dark blue due to "being stupid now", and while Catti hasn't joined the party either, she does have a talk sprite, along with Jockington, the only two classmates who have talk sprites but haven't joined the party yet.
• What if all eight students except for Kris will be party members in later chapters? If Kris is evil and can no longer be controlled due to not having a SOUL any longer, maybe there'll be another way to have control that doesn't involve Kris at all.
• Asriel might be the Seventh/Eighth Ranger.
• There may even be a ninth party member colored gold (associated with determination, and obviously the golden flowers), colored differently enough from the yellow party member like Asgore's flowers. Or maybe not since, just like red and white, gold is also an "odd one out".

Kris, Susie, and Noelle will be there to meet the Vessel.

Trying to name your Vessel after these three gets the message "You're about to meet someone wonderful."

What else does the narrator describe as wonderful? The vessel itself.

• Many names will result in the "someone wonderful" message, including Berdly, Catti, Jockington, Sans, Papyrus, Toriel, Asgore, and many others.

The Heroes are actually Frisk, Chara, and Gaster.

A human, a monster, and a prince from the dark.

Basically, the Fun Gang isn't the chosen Heroes, but this trio. Only Jevil is aware of this, and so he does not treat them as the Heroes.

• Chara isn't a monster, though, unless you're saying Gaster is the monster and Frisk and Chara are the human and the prince.
  • Perhaps it means a figurative monster?
    • Chara is clearly a "monster", even in the literal sense.
    • Chara isn't a figurative monster by their own will, though; You corrupt them into a monster during the Genocide Run, the same way you did with Noelle on the Weirs Route.

Ralsei will try to trap a Lightner in the Dark World so that he can go to the Light World along with Kris

It will be similar to the game Ib where Mary tries to keep Garry trapped in the gallery so that she can escape with Ib. In Deltarune, maybe Darkners can only enter the Light World when their Lightner counterparts are present within the Dark World. Ralsei, scared that Kris and Susie may never return to the Dark World, will trap his Lightner counterpart Asriel in it and enter the Light World along with Kris and Susie without them knowing, "replacing" Asriel as Kris' brother, like how Mary became Ib's sister in one of the endings where she escapes.

Alternatively, Susie will be the one trapped in the Dark World, making her the "Garry" of the story with Kris being the "Ib". She'll either get trapped along with Asriel because she found out about Ralsei's plan, or get trapped instead of Asriel because any Lightner is required to stay in the Dark World in order for a Darkner to leave, not necessarily the Darkner's counterpart. Not to mention Ralsei didn't get along with Susie as well as he did with Kris, and the fact that he told something to Kris that Susie (and the player for that matter) couldn't hear while they were in jail is already pretty suspicious.

If not Asriel or Susie then Noelle could be Ralsei's target instead, especially since he isn't as close to her compared to Kris or Susie (plus as of Chapter 2 Susie and Ralsei grew closer after hanging out at the fair together, though he's still hiding whatever he's telling Kris from her). The Delta Rune carpet in Kris' room in the castle, likely based on Ralsei's interpretation of the symbol, has the triangles colored blue, pink, and green like Kris, Susie, and Ralsei, and the winged circle colored white like Noelle's dress, possibly implying that (if Noelle isn't actually the Angel) Ralsei is planning to frame Noelle of being the Angel and convince Kris and Susie to defeat her.

Presumably a Lightner (or at least a monster) must turn to dust in the Dark World in order for their physical form in the Light World to disappear and allow a Darkner to take their place. The dead Lightner will then become a Darkner just like how Garry becomes a painting of himself if he dies in the gallery. In the Weird Route Berdly was frozen instead of turning to dust and his body remained in the Light World, so Ralsei wouldn't have been able to take his place.

It's also worth noting the similarities between Ralsei and Mary:

• They both primarily wear green, a color that can symbolize envy (Mary got jealous of Garry for his friendship with Ib, maybe Ralsei will get jealous of Asriel and/or Susie for their relationship with Kris).
  • Interestingly, Kris' Light World design shares similarities with both Ib (brown hair, red eyes) and Mary (green clothes, carries a knife), and Susie's with both Ib (long brown hair) and Garry (purple color, blue jacket/coat, overall ragged clothes) as well. Noelle happens to have long blond hair like Mary too. Kris and Ib are also both silent protagonists.
• They're both residents of the world (Dark World/art gallery) that the outsiders (Kris and Susie/Ib and Garry) fall into: a Darkner and a painting/artwork, respectively.
  • The Darkners and artworks in general also have something in common: they're both inanimate objects that somehow came to life.
    • While it hasn't been confirmed that W.D. Gaster was involved in the creation of the Dark World and/or Darkners, it's quite suspicious that he shares the same first and last initials as Weiss Guertena, who created all the artworks and possibly brought them to life in Ib.
• They both have their own "area" (Ralsei's kingdom/sketchbook area) with a subarea that they don't want the protagonist to enter (Ralsei's room(?)/Mary's room).
  • Since Mary's picture frame in her room has to be burned down in order to defeat her, what if Ralsei's castle also holds something that could potentially be used to defeat him (maybe that one dark fountain)?
• They both stay with one of the companions (Kris/Ib) while the other is temporarily separated from them (Susie/Garry). There's even a brief perspective switch from Kris/Ib to Susie/Garry, though the player doesn't get to fully control Susie like they do with Garry.
• They were both lonely and wanted to have friends, waiting desperately for someone to arrive in their world.
• Asriel (not Ralsei himself, at least for now) and Mary are both associated with yellow flowers.

Undertale was heavily inspired by the Mother series, perhaps Deltarune will be at least partially inspired by Ib?

Noelle and Susie's relationship won't pan out, or at least won't go as we're lead to expect

With one being physically strong, aggressive and tomboyish, and the other anxious, buck-toothed and nerdy, it would run a pretty high risk of just being a rehash of Undyne and Alphys if they were to follow a standard romantic plot, so either some sort of major subversion or bait-and-switch will be done or they simply won't end up together at all.

• Some possible scenarios:
  • Noelle will confess to Susie — who's straight.
  • Susie is attracted to women (whether exclusively or in addition to men), but Noelle's not her type.
  • Another possibility, which ties into the "your choices don't matter" narrative, is that Susie is aromantic and perfectly happy just having friends, which would invalidate any romantic choice the player made for Susie.

Lancer is the actual third hero.

Indisputably a Darkner Prince, 'nuff said.

The third hero is neither Ralsei nor Lancer

Just in case they both turn out to be Red Herrings.

The prophecy about the Three Heroes was false, but the description of the Roaring is true

• Ralsei made up that prophecy about Three Heroes coming together to banish the Angel's Heaven in order for Kris and Susie, aka a fairly clever human with a powerful SOUL (even without the one possessing them), and a really brave monster strong enough to beat nearly everyone in the first Dark World, to team up with him to stop the Roaring from happening. It ties into the fact that Susie and potentially Kris, under the orders of the player, not acting like heroes is the one thing that Ralsei doesn't know how to deal with (even the King of Spades rejecting a pacifistic outcome and forcing a violent one doesn't deter him). The legend in itself is also very vague, with only Kris not being interchangeable for another character yet, and the description of the end of the world being very generic and not specific at all. Ralsei is also the only one to refer to it at all.
• In contrast, the Roaring prophecy is probably the only moment where Ralsei completely drops his relentless kindness and politeness and tells off anyone in the game so far. His description of the Roaring is to the point and pragmatic with details, unlike the flowery language of the first one typical of RPG prophecies, and there are references to the Roaring outside of Ralsei's monologue (Jevil mentions a roar bubbling from Hell, Queen refers to the Knight as the Roaring Knight, and the motifs on the body of the foreground Titan appear in the void-like area before Castle Town).

Kris is actually a Decoy Protagonist and Susie will be the true protagonist the player takes control of.

During Chapter 1, Kris never shows much of a personality, nor do they have a significant effect on the events of the plot. Instead, all of the major developments are spurred on by Susie and her friendship with Lancer. It is Susie that receives all of the character development, starting off as a social outcast and bully to becoming close friends with Lancer and subsequently Kris and Ralsei. And it is this friendship with Lancer that spurs him to overthrow his own father in the "good" ending. In addition, the POV of the game temporarily shifts away from Kris to Susie at one point, further advancing the notion that she will be next player character. Finally, the fact that Susie has a set background and personality actually fits the theme of the game, since it's explicitly stated that choices don't matter and people cannot change in the world of Delatrune, making it only natural that the protagonist be a scripted character and not an anonymous self-insert.

• Susie drives the whole plot: you get into the Dark World because of her, you spend a good chunk of the game chasing her as she runs rampant, she can't be controlled in combat until very late in the game, and the entire chapter is a story of her character development. She is the protagonist whose choices will matter and shape the story.
  • Furthermore, her sole ability has the name Rude Buster, which is also the name of the theme for random encounters. Unless every other chapter has its main battle theme named after the abilities of the party members, that's a big hint that she's the protagonist, or at the very least very important to the story overall.

Ralsei's empty kingdom and Kris's empty room are the same, each other's equivalents in different worlds.

Therefore, the goal of the game is to either fill Ralsei's kingdom with subjects, or to help Kris get their life together and decorate their room with useful and sentimental objects alike — and both of these changes will reflect in the other realm. Ultimately, Ralsei is a true prince again, and Kris is in full mental health with true friends to rely on.

Ralsei deliberately took an opportunity to have a conversation with Kris alone, while the player's attention was on Susie and Lancer.

While Kris and Ralsei are imprisoned, Ralsei pointedly suggest that Kris close their eyes and focus their thoughts on Susie — at which point the player's attention shifts to her until she makes her way to free Kris and Ralsei. When she does, when the scene cuts back to the pair of them, Ralsei has this to say to Kris:

• "... so that's why, OK, Kris?"

The clear indication is that they were having a conversation about something that we are not privy to, but that Ralsei and Kris clearly are. This was not a mistake or oversight, nor was it merely narrative convenience on part of the story as a whole; Ralsei wanted us to not hear what he and Kris talked about in our absence.

• Perhaps Ralsei was discussing about how Kris' choices don't matter.

Ralsei's secret conversation with Kris is the real reason they got rid of the SOUL.

As stated in the WMG above, Ralsei took an opportunity to talk with Kris when we weren't around to hear ("... so that's why, OK, Kris?"). This is the beginning of a conspiracy between the two, against us, the player — because we are a villainous, possessing creature making them dance to our tune like puppets.
Kris didn't rip out the SOUL because they're going to turn evil or kill anyone, or even because they wanted a slice of the pie (though they may still grab some). They got rid of us because they now know of us, thanks to Ralsei, and want nothing to do with us.
This is the point where the counterattack begins.

• Another thought is that we would be the flaw in the prophecy. That the extra SOUL occupying Kris would somehow prevent the prophecy from occurring, and cause ruin. Thus, Kris removed our influence, because we're not part of their story. Our role may be separate (guiding Susie, Noelle, Lancer, and others to act as the supporters of the prophecy), or we are actively the problem.

The identity of the true three heroes (and possibly even the Angel) will change depending on which route you play and/or which save slot you use.

So for example, in one instance, the three heroes could be Kris, Susie, and Lancer, while in another instance, they're Kris, Noelle, and Ralsei, and so on. However, the ending will always be the "same" regardless of which characters turn out to be the true heroes and the Angel, with either the heroes successfully banishing the Angel's Heaven or failing to do so.

The three heroes are Chara, Asriel, and Frisk

In Undertale, there's implications that one of those three characters is the Angel of the prophecy. In Deltarune, their roles will be flipped so that they're now the greatest opposing forces against the Angel.

Specifically, Chara is the Human, Asriel is the Monster, and Frisk is the "Prince" from the Dark (the title "prince" could be either metaphorical or an alteration made by Ralsei), based on the theory that Frisk is Chara's Darkner counterpart. Or maybe Frisk is the Human and Chara is the Darkner.

• Frisk is Chara's what?

The three heroes are Frisk, Rouxls Kaard (or Seam), and Ralsei

AKA three characters that are (presumably) the Darkner counterparts of Chara, Gaster, and Asriel, with the Lightner counterparts being the main antagonists as the "Queen" (metaphorical title), the Knight, and the Angel respectively. After all, it's never been clearly stated that two of the heroes must be Lightners, just that one is a Human (Frisk) and the other is a Monster (Rouxls Kaard/Seam). It's also possible that "from the Dark" isn't just a descriptor for the Prince, but for the Human and the Monster as well.

• The Queen part has been jossed, while Rouxls and Seam aren't Monsters, but Darkners.

The three heroes are Chara, Gaster, and Ralsei (or Asriel)

AKA three "Demons" that will oppose the Angel:

• Chara calls themself "the demon that comes when people call its name".
• Gaster is associated with the number 6.
• Ralsei is presumably the Darkner version of a headband with demon horns, and Boss Monsters in general are a bit like demons appearance-wise (goats with fire powers).
• If "from the dark" is metaphorical and not literal, it's possible for Asriel to be the third hero instead, especially since he's a sort of "fallen angel" in Undertale.

Gaster is two of the heroes

Based on the whole "Gaster is a fusion of two characters" theory. For example, if he's a human/monster fusion, he could be both the first and second heroes. Of course, this theory wouldn't work if he's a fusion of two of the same species, like two monsters for instance.

The three heroes are the (owners of the) three SOULs that got combined into the single SOUL we play as

That's why the SOUL can be used to seal the dark fountain, as the prophecy said the three heroes are the only ones who can seal them. That would mean the three SOULs belong to a Human, a Monster, and a Darkner Prince. Ralsei knew about this, but lied that he, Kris, and Susie are the heroes in order to become friends with them.

Each of the Main Characters has a different psychological issue and they're collectively coping/recovering.

• Kris has a variation of PTSD and the dual shocks of the divorce and Asriel leaving have recently rocked their world. It's a struggle for them to cope with so much of their support structure gone, but with Susie on the mix, they have a chance to start recovering again.
• Susie comes from poverty, but doesn't want anyone to know. She worries about the possibility of getting expelled, but remains heavily defensive to avoid breaking down. Kris teaches her to open up little by little and helps her cope without constantly inducing fear in others.
  • On top of that, as stated in an above WMG, it's possible her parents are abusive to her (or just her dad, with her mom either suffering with her or possibly even out of the picture, given how much she approves of Lancer's new "jail is only for dads" rule), leading her to having violent tendencies of her own as a coping mechanism. It's entirely possible that her friendship with Lancer spawned partially because of both of them having rough home lives. Kris will help her find healthier ways of coping with her situation that won't alienate her from her classmates, and give her the courage to speak out about the abuse she's suffering so that it can be put to a stop.
• Ralsei is an Extreme Doormat unable to stand up for himself solo. He craves affection but doesn't do so well meeting people and tends to bow to their demands regardless of how he feels. Kris and Susie help build his self-confidence as well as letting him learn to deal with people.

The theme of your choices not mattering won't be so set in stone as it's initially played. Nobody can choose who they are; these characters' problems won't magically disappear on their adventures nor ever fully leave, but you choose how you react to it.

Kris, Susie, and Ralsei really are the true heroes of the prophecy

Anything throughout the game hinting at any of the heroes being someone else (i.e. Lancer being a Darkner prince) are just red herrings.

Noelle will replace Ralsei at some point.

It's no secret that the fanbase absolutely adores Ralsei. He's cute, helpful, and overall a kindhearted individual. Unfortunately, as he's a character in a Toby Fox game, there's a good chance that he might not stick around for the end. He might wind up getting Killed Off for Real, he might pull a Face–Heel Turn, or he might've been Evil All Along, but no matter what happens, Ralsei will no longer be with the Fun Gang.

Ralsei's absence will leave an immediate hole in the team's dynamic, leaving Kris and Susie without a healer or a way to Pacify enemies. However, thankfully for them, there's someone who can step up as his replacement: Noelle. Noelle comes off as similarly kindhearted as Ralsei, and her Dark World outfit is reminiscent of a White Mage, both of which lend to the idea of her being similarly adept at healing magic. Adding to this, her name evokes the "You will meet someone wonderful" message in the Vessel Creator, just like Kris and Susie, further hinting that she might become a playable character.

Noelle will gain the ability to save and load.

The Queen mentions she has determination and in the alternate path, one save point mentions both Kris and Noelle are filled with its power.

Noelle will have a Face–Heel Turn.

She was this close to creating another fountain with Berdly even though at that point her only experience with dark worlds was a dictatorship and she believed that creating more fountains would cause the Queen to rule the world, just because she personally found her adventure enjoyable. Maybe she is not as kind as she seems. Maybe, if her regular life got worse, through, say, her father's death, she would even prefer an eternal war against the Titans to it. Also, she's the angel of the prophecy, the heroes must destroy her heaven. It's set in stone they must fight against her. And in chapter 2's alternate path, she ultimately considers killing enemies and even a merchant to be worth it if it means getting stronger.

Noelle will create Replacement Goldfish of her family.

Similarly to how Kris as the Knight created Ralsei. Dess is implied to be dead, Rudy is dying, and Noelle's mother is extremely distant due to her work, similarly to how Asriel has become distant to Kris due to college.

Noelle will kill Kris in the Snowgrave Route.

Because if you lift the concept of having a partner who knows a spell that kills from Pokemon Creepy Black, why not lift the ending? Either she will absorb their soul and we will continue to play as her, or the Snowgrave Route is Unwinnable by Design (Deltarune has only one ending? Game Overs aren't endings).

• Er, Game Overs are sometimes endings.

Ralsei is taking up the party slot that was intended for Noelle.

He has a crush on either Kris or the Soul and forces his way into the story, literally living out a Self-Insert Fic.

• Ralsei is a Moveset Clone of Noelle with the nukes removed in accordance to his pacifist beliefs.
• Chapter 2 puzzles are designed for 3 characters, and Ralsei's addition causes problems with some of them.
• Most characters in Chapter 2 don't acknowledge his presence as a member of the party — he's seen as another NPC in the wrong place at the wrong time. At least until he drops a Plot Twist on the Queen and she trusts him immediately.
• He is at least somewhat aware of the upcoming plot (knowing to speak to Kris in secret when a cutscene is focused on another party) and outright freaks out when a cutscene gets derailed in the Weird route — possible in part due to his actions.

The Heroes are aware of the fourth wall, and are steadily derailing the plot in a fit of Rage Against the Author of a story they must play out again and again.

• Kris is relying on a Despair Gambit, pretending to the SOUL that the world is ruined and there's no need to play further — first imitating Undertale's Chara ending stinger, then opening another fountain to bring the world closer to its doom.
  • They're also most shaken by the fight with Spamton, who succeeds in breaking free from [Heaven]'s strings only to drop lifelessly to the ground — just because it reminds them that making the SOUL go away might also be their real death.
• Ralsei tries to maintain the plot to his best ability, but does just enough changes to stick close to Kris. Whatever he discusses off-camera has to do with trying to avoid Plot Holes.
• Susie, with her mantra that no decisions matter, becomes a Thrill Seeker, putting the party into dire straits at every opportunity, because she knows she has Plot Armor as a main character, and the worst thing that could happen is starting everything over.

Ralsei told Kris about the Roaring and titans during Chapter 1 while the player was observing Susie.

Ralsei wanted to make sure that the player wasn't listening out of distrust and concern that the player would sabotage his mission. Noelle's and Berdly's idea to create a new dark fountain gave him no choice but to tell everyone present about the Roaring, the player included.

Ralsei and Kris have "met" before the events of Deltarune, but Kris doesn't know it.

Going off the theory that Ralsei is the devil horn headband that Kris used to own, Ralsei may have been sentient at some point within the Light World. Toriel mentions that Kris wore their headband everywhere, explaining how Ralsei may have known about specific locations despite never having left the Dark World. He may not have had a way to communicate to Kris in the Light World, similar to how Lancer cannot speak as a regular playing card, but he could have learned the names of Kris and Susie regardless by overhearing them after the headband was lost

Kris and/or Ralsei are victims of Gaster's manipulation

Like Jevil and Spamton.

Kris somehow made a deal with the SOUL

I'm not entirely sure how, but they did. The deal? That no matter what the SOUL did to Kris or the rest of their friends, family, and neighbors, that they would only help Susie, not corrupt her. It's the only reason I can think of why Susie doesn't have a weird route in Chapter 1; even if you do beat up everyone and get the Darkners to want to kill you, she will always stop before killing Lancer or any Darkner, even though she's the most likely to commit murder in their entire class. Why would Kris make this deal? Because they like Susie…

Ralsei is aware of the Player controlling Kris and is trying to help them break free

The real Heroes are long dead.

Which is why Kris can't seal the fountains out of their own power and Susie and Ralsei can't at all, despite the prophecy specifying that the heroes can seal the fountains. Both the Prophecy and Roaring cutscenes depict the poncho human who died millenia ago experiencing the Roaring, which means that the events of the prophecy were supposed to happen much earlier than they did. To rectify this, Gaster called us, the player behind the true hero, which is why we are the only thing which can seal fountains.

The real heroes are Nubert , Real Starman, and Sans.

Noelle is Pastafarian.

When Noelle thinks she's dreaming, she mentions "the skyline gleaming like Holiday lights", Holiday being capitalized. Holiday is a Pastafarian holiday.

Noelle will permanentely rejoin the party as a fourth member, complete with the HUD being adjusted to accommodate her.

Ralsei may fear that this makes him redundant, but will eventually gain an upgrade to his healing abilities that balances out with her access to Sleep Mist.

In the Weird Route, this may lead to the SOUL's/our more reprehensible actions in at least Chapter 2 getting exposed.

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