AHAH I do tend to see such face value discussions. If you're interested in my thoughts on it all, then, sure...! I feel everything Does have significance in one way or another.

JEVIL - The playful rowdy boku-pronoun silly-willy who used to tussle with the diligent, loyal, capable Court Mage. This sounds to me like a pair of OCs Kris & Asriel used to enjoy playing together as kids. After all, Asriel is said to have favored a purple mage girl in smash (Seam uses 'atashi' ?! which has multiple interpretations...). Seam is a very, very old plush, seemingly older than the other Darkners, which would track with them having been Asriel's old toy, and thus feeling very Ancient to Kris (who is younger!). Jevil is giving major Little Brother energy, to me.

JEVIL is a troublesome rascal who draws well-behaved Seam into shenanigans, but who Seam does not hate or resent for this. Seam is nostalgic for how Jevil made things interesting, and their games. Feels a kind of regret for missed opportunities. Would Now like to see chaos flourish, before they dilapidate.

I would see this dynamic overall as representing the well-behaved Asriel constantly towing the line, doing as parents ask, getting good grades, engaging in extracurriculars, attending choir, while Kris is the rascal who does as they so please. I'm sure if Asriel could go back... they would see towing that line was pointless. What has it lead to? Forced to abandon Kris off to college, to suffer alone and lonely, to toil in normiedom. Why not blow it all up? Why not ruin it all?

Kris had been out there inserting swears into Christmas Carols, sleeping through class, terrorizing the girl next door... such a Jevil.

All of DELTARUNE feels as this to me. Asriel wanting to see the structured world he helped maintain for so many years, finally burn. The Court be struck down, the rulers dethroned, our Purpose ignored & displaced. What did Jevil know all along, that Seam did not? Was Jevil really the fool, or was Seam the fool, following imaginary rules and restrictions? What more is possible for us, outside of these strictures? Seam is excited to see something 'new', finally. I think Asriel is, too.

SPAMTON NEO - Asriel & Kris canonically once attempted to create a video game, with Kris studying video game music (seen in Queen's prison) & Asriel contributing God knows what. We know the CD inserted into SPAMTON to turn him into NEO was some sort of failed attempt at a rainbow-winged 'final boss' Asriel & Kris had attempted to implement into their own game. We also know Kris & Asriel collaborated on an 'angel' doll that was never completed, as they spent too much time attempting to decorate it with giant rainbow wings.

We also know Kris & Asriel collaborated on artworks depicting their worlds using MS paint (Swatch represents this icon) (their computer background is an image they collaborated on & signed).
So in every inherent way, this boss may portent what Asriel & Kris see as Final Boss Material, AT LEAST AT ONE POINT IN TIME!! Perhaps a more youthful, crude vision of a game boss?
Obviously this NEO isn't quite the Final Vision as intended, but may be nostalgic.

As for Spamton himself. I'm insane and think he is a character Asriel utilized to break rules and engage in an underhanded, hidden way. We know Noelle received e-mails from Spamton as a child (I cannot stress this enough, He Is Not Real And Does Not Exist), and was given files that would corrupt & modify her CATPETTERZ/petz game (based on P.F. Magic's Petz series from the 90s, which has/had a VERY active mod community I engaged with a lot as a kid!). We already know Kris & Asriel were attempting to make games, and had such abilities. So obviously, one or both of them were fucking with Noelle. More on ROMhacking later with ERAM, but obviously Kris & Azzy engaged in ROMhacking.

It is possible Kris & Asriel both 'played' spamton... but idk... he's Giving Asriel to me. The insults, mockery, resentment, but also weird compliments, evoke Flowey to me.

His favorite year is 1997, which I would charitably like to think of as When Kris Came Into the Household (maybe Asriel's birth year was like, 1992 or something, giving them a 5 year ageegap). This is my own conjecture. Spamton mentions Kris being in a dumpster. Was Kris a dumpster baby lol? Did Asriel discover Kris and bring them home, much like Asriel found Chara in UNDERTALE?

If I follow my own insane logic with Azzy playing Spamton, we would see a depiction of an underhanded, seedy guy who selfishly wants to take over & degrade everything, as kind of what Asriel Feels Like he becomes when he Tries to misbehave. What it FEELS like to secretly infect the girl next door's computer.

Its also worthy of note that Spamton would ATTEMPT to infect Queen's palace in the past, but her firewall/adblock/spam protection prevented this; Dess never opened Spamton's obviously fake bullshit e-mails, as she was not as naive as Noelle, who would simply download them directly into her game lol. The only way Spamton can infect The Laptop (which Dess used) is if Kris themselves HAND DELIVERS Spamton access INTO the palace. To me this implies Asriel using Kris as a tool to reach places he is too afraid to. Because Kris is willing to be nefarious lol...

I guess I'd say Spamton's fight Gets to Kris more than any other, because it doesn't respresent their Own feelings (like Jevil or Pink do), but Asriel's, which are more upsetting to engage with... because Kris loves Asriel, and may worry about what they are doing to their brother.

ERAM - MANTLE is obviously Kris & Asriel's ROMhack of Catpetterz RPG. Some assets have been entirely replaced according to their own fixations (the SHELTER fully rendered in), while others are completely unchanged from Noelle's description of the original game (the ICE PALACE). It is incomplete & abandoned. I would assume this ROMhack was an early endeavor in video game programming... perhaps made some time before the NEO final boss programming attempt? Or after...? Well, we don't know...

TENNA ironically ROMhacks their ROMhack to make HIS video game. Because I think Tenna was a character of Kris's, this makes sense to me.

ERAM. Looks like Asriel. Am I insane? This feels obvious. There is also fire magic & the kind of loving, obsessive dialogue about Kris's true heart & desires, as we recall from Flowey in UNDERTALE. It is a kind of loving masochist stoking the fires of their sadist's urges. Watering Their Own Thorns, one might say (:

Like SPAMTON, I think ERAM unsettles Kris Because it does not Evoke their own voice, but Asriel's. Thrilling, possibly nostalgic (if this is an old project of theirs), alluring, exciting, terrifying. Asriel has a kind of... intoxicating madness to him... I would describe ERAM's dialogue as seductive, PERSONALLY. Knows what you really want, knows what stimulates you, deep down. Knows this nonsense is not what you Really Want. Knows you can't share this with anyone else. Knows what you're hiding. Of course this dialogue makes Kris sweat, makes their eyes flicker with burning desire...

Oh yeah! And the game console is obviously under Asriel's bed, with Asriel's controller (with janky pink & yellow buttons, likely a bootleg replacement for buttons that broke from overuse, which would come in all sorts of garish colors, back in the day...).

GERSON - Alphys is a new hire at the school (and new to this town overall), and Alvin's dialogue implies Gerson passed away fairly recently. Gerson likely used to teach Asriel at the school. I believe Kris & Asriel both create Darkworlds, and Asriel's reflects his memories of Gerson.

Not much more to say beyond that, other than, Gerson makes me think about transformative works & derivative fiction ... he is effectively a scholar of the bible, who eventually wrote Bible Fanfiction. That Bible Fanficiton later was again iterated on in the form of games suchas CATPETTERZ RPG, which are then further drawn apart from their source by Kris & Asriel modifying it with a ROMhack, MANTLE.

We don't have to accept what was written before us, we can rewrite it. We can impose our wishes on this world & contort it to our desires.

I wonder what conversations Gerson may have had with Asriel. Asriel was also an active participant in church, so... possibly a lot of exposure there. I wonder how that may have influenced Asriel's fiction itself.

PINK - So starkly this represents Kris's struggles between BODY & SOUL. Conflicting desires, wrestling... subject to urges beyond your control, urges which may influence your actions, may betray your intentions, may contradict, may consume you.

As these are a representation of Kris's struggle, ""Ralsei"" is the one compelled to offer comfort & advice, wishes for Pink to seek parity with self, to not divide in hatred, or shame. Accept the body's requests, as it must be nurtured... it is your body. If you fight it too harshly, you may lose what the body offers to you. You may fall apart. It isn't sustainable, this warring...

Compare this to SPAMTON, who Asriel offers no comfort & wishes to distract Kris from, write him off as just some wayward program, nothing important. IIII Think it makes sense for Asriel to downplay representations of his own suffering, but take Kris's seriously.

I do not PERSONALLY think the BODY & SOUL are different people. I think both are Kris. And represent Kris's own impulses, desires, some more earnestly than others. I do not think "the player" "the vessel" is anything distinct, I also Literally don't know where people even got this idea from UNDERTALE, as both Chara & Frisk have their own capabilities & omit a player from control respectively. We cannot create new dialogue options, or new endings... we, as the player, are subject to only what Kris's mind comes up with, gives us to work with. I Do Not See people making this argument about Link or Mario, so I don't know why it exists at all for Toby's games.

and finally. I will just say. I think Another Him refers to Asriel (who is referred to as this ominously in UT's soundtrack), and I think the voice speaking to you as you create 'the Vessel', is Asriel. And he's testing some mechanism, and Kris's memories. If Kris is properly amnesia'd by whatever they have chosen to endeavor together. By asking crude baby questions suchas Kris's favorite flavor and color, and name, Asriel can douse if the magic is Working as intended, or if something is wrong. I think the tone it speaks in is again that kind of oddly seductive tone we hear in various representations of Asriel in UT & DR. I believe, at the moment, that Asriel wishes to know what it is Kris really wants, thinks.... is your favorite color even what I know it to be? And perhaps the reverse is true, depending on what Ralsei 'is', what Asriel has Done to make him exist. I'm insane!!!!!!!!!!!!!!!!!!!!!!!!!!! So perhaps bare all of that in mind when reading my personal present interpretations on the game & bosses. Thank you [falls down the stairs]