The phone voice and Carol are not the same person.
(Deltarune Chapter 4 + Weird Route spoilers.)
I've heard people say "the voice is closer in the Weird Route ending so that's why it sounds different" but it's not. The voice on the phone (which I'm assuming is the Knight) sounds different then Caorl's Weird Route voice mail, when both scenes have Kris right next to the phone.
The only difference is in the Holiday Mansion phone call we're in Kris's other hand. Meanwhile, the were in the cage in the weird route voice mail. If anything the ending phone call in the mansion should sound clearer.
So why does the phone voice say "I'll be right there."
It's talking about the Dark Fountain. Earlier, it says the Dark Fountain would be in the church "tonight," but after the mansion hangout happens, there's a dark fountain in the afternoon.
It's clear that Susie getting the guitar bumped up the Knight's plans, so they decided to create the church fountain earlier.
This goes into speculation but it might explain why they stay in the church. Because the Knight cannot stay in the light world for prolonged periods of time, and less so at day time. It didn't have time to set up a head Darkner and everything and leave (which explains y'know, the titan summoning at the end.)
As far as the Knight knew, Susie likely had the code to the bunker and would be able to break in after this fountain. (She didn't as she didn't get to write down the code though.)
So, this fountain is a last ditch attempt to maybe start the roaring by summoning a Titan. This reeks of an act of desperation.
Then why does Carol show up right away?
Asgore tipped her off.
Think about it? We already know that Asgore is Carol's gardener. And we already know there's something really suspicious going on with Asgore. (Which is presumably his search for Dess.)
This goes into "Hometown Conspiracy/Hot Fuzz cult" theorizing, but seeing as Asgore's allowed into Carol's room, (plus all the conspiracy board stuff that's likely Dess related,) he's likely in on whatever conspiracy is going on. If Dess's disappearance is related to the bunker, he likely knows one of the codes is hidden on Dess's guitar.
So, here's the chain of events I see happening...
Kris calls the Knight to warn them that Susie has the guitar. In response they bump up their plans and make the Chapter 4 dark fountain early.
Shortly afterwards, Asgore overhears Susie playing the guitar.
Asgore quickly calls Carol to tell her someone has December's guitar and they might learn the bunker code. She immediately leaves the town hall.
Once Asgore sees Carol's car arrive, he goes to check who's playing the guitar, with the snack trail as a convenient excuse.
Carol arrives, and takes the guitar.
The fact that Asgore pauses eating at the mention of "a code" is extra suspicious. Almost like that confirms his suspicion that Susie and Kris were looking for the bunker codes.
It all adds up together. Carol may still be working with the Knight but I don't think she's directly the one on the phone call. Chapter 4's prophecies have already suggested that the Chapter 5 Dark World would be flower king. It makes sense if Asgore's interfering with our Bunker-Code search if it's connected to whatever he plans to do in Chapter 5.
Anyway that's why the Roaring Knight is Dess and not Carol. Have a good day.
The Significance of Susie, Rude Buster, and The Prophecy.
(This has spoilers for 3-4)
This is a bit of a long post, but it's an important one, I think.
Let's talk about Susie's signature spell, Rude Buster. I genuinely think there is thematic significance to this spell.
To get to why, though, I want to go over everything.
Rude Buster is a spell that Susie knows from the moment we meet her in Chapter 1. It costs 50% TP, and, as the description tells us, it inflicts moderate "rude" element damage to one foe, and uses both Attack and Magic in its calculation.
It considers defense in its calculation, and it scales better with Attack than it does Magic.
I want to compare this spell to another spell, Iceshock.
Iceshock inflicts "magical ICE damage" to one enemy, and costs 16% TP. It scales purely with the Magic stat, and is unaffected by her Attack stat. It also cuts through defense.
On the surface, Iceshock is generally the better spell, it would seem. It might not deal as much damage at first, but it's significantly cheaper than Rude Buster, ignores defense, and scales like crazy when Noelle becomes Stronger.
While this is speculative, it almost comes off as if Iceshock is being more 'properly' cast. It's described as 'magical', it seemingly instantly surrounds an enemy rather than needing to be aimed, it ignores defense entirely.
But... I think there's a bit more to it than that. Noelle's magic is kind of distinct from Noelle herself in a way. There's some level of detachment. There's distance. This is (partially) why we're able to manipulate her so easily into getting stronger. It's easy to not think about it. They're just enemies. Etc.
But Rude Buster? It's a direct extension of Susie herself. She might not be directly naturally talented with Magic, but hell if that'll stop her. She channels everything she has into her axe and sends it out as a bolt of rude energy.
My point is this.
Iceshock deals perfect, magical damage to an enemy, piercing defense. It's better than a Susie crit at first, and it scales drastically. It's simple, and it's cost efficient.
Rude Buster is a direct extension of Susie herself. It's her raw emotion channeled into a single attack. It's her willpower, her resolve, her hope, all imbued into one little spell.
Rude Buster as a spell is, either symbolically or literally, Susie's resolve.
This is why it is a "Rude" buster. What does it mean to be Rude? To be impolite. To not follow the rules, the expectations. And, if there's one thing Susie excels at, it's breaking every single expectation anyone might have for her.
Is it truly by chance that, out of everyone in the party, it is Susie who talks back to the Roaring Knight?
Is it truly by chance that the only party member who can actually do anything of substance against The Knight is Susie, with Rude Buster?
Kris is (in most circumstances) holding back. Susie and Ralsei are able to deal chip damage. But Rude Buster, through sheer force alone, overcomes the Knight's defense, not by being magic or anything like that, but simply because it's that good.
Consider also The Titan. Everything seems bleak, the Titan can regenerate, and there's nothing we can do. So what do we do?
We call upon Rude Buster. Technically it's "Dual Buster", but...
Susie and Gerson are both clearly casting variations of Rude Buster here.
And it works.
And, lets think on that for a moment. Gerson also knows a version of Rude Buster. ...Why?
It's not like Gerson doesn't have his own magical attacks he could have used here, right? They could've easily done something else for this. But... No. Gerson casts his own Rude Buster. Why?
Well, think about what Gerson stands for. He believes, in the same way Susie does, that the Prophecy isn't all it's cracked up to be. He believes that it can blind you, that it's better to read between the lines.
As a Secret Boss, his philosophy is "I don't care".
So, to me, at least, it makes perfect sense that he would also know Rude Buster. Because, just like Susie, when confronted with the fate of the universe in bold text, he simply laughs it off.
This is also, I believe, why Gerson is the only character who can outright reflect Rude Buster.
Because while Gerson might not have the same resolve to change fate as Susie does, he is driven in a similar way.
The Devilsknife reduces Rude Buster's TP Cost. Why? Is it just because logically a jevil-turned-scythe would be good at channeling Magic?
No. Think about what Jevil stands for. He believes that because his choices do not matter, he is free of consequence. He can "do anything", because his choices are irrelevant. If he could somehow be punished, then, well, his choices would've mattered, then, wouldn't they? And he knows that's not true.
So he does whatever he damn well pleases.
Obviously, Jevil and Susie are not really comparable- Jevil fully accepts that Fate is unbreakable, and Susie very much seems to think The Prophecy is bogus by the end of Chapter 4.
But, I think the throughline is there. Devilsknife makes Rude Buster easier to cast, because by nature, Jevil is already used to doing whatever he wants and ignoring the 'rules'.
I hope I've made my case clear. But there's even more.
This may well be where I lose you, to be clear, so I hope you take everything I've said about Rude Buster as its own thing, and consider the rest of what I have to say as an extension of that. If you don't believe what I'm about to say, that's totally fine.
Without further ado...
Let us consider... The Prophecy.
The Second Hero of the Prophecy is "The Girl, with Hope crossed on her heart."
As many before me have pointed out, this depiction... does not quite look like Susie. The weapon is wrong.
This is a much longer discussion and I don't think I can quite fit it into this post, but, in essence, I believe that this was supposed to be Noelle Holiday. Noelle actually can equip a few swords as of Chapters 3-4, surprisingly. She can equip the Jingleblade and the Blackshard.
However, I don't believe that Susie is "not" the second hero. I believe that The Prophecy has been tampered with. Or, at least, reinterpretted.
Think back to what Gerson said. Stories can be changed. They can be retold.
Cat Petterz the RPG is a ripoff of Dragon Blazers, which is a retelling of Lord of the Hammer, which is a retelling of The Prophecy, which is a retelling of DELTARUNE.
I believe that this sort of thing is happening to the prophecy itself. I believe that Gaster, for one reason or another, changed the prophecy, replacing "The Second Hero, The Girl" with Susie. This sort of rules lawyering is possible because Susie is also referred to later in the prophecy:
We know that this is Susie because Rude Buster is being used to identify her. This image is even called "Rude Buster" internally.
I believe the original prophecy was introducing Susie as a different "The Girl". However, because it technically uses the same term to refer both to Noelle and Susie, their roles can be altered. And so, Susie, through Gaster's intervention, became the Second Hero.
But why? Why was it important to make Susie involved?
I believe it's simply because of who Susie is. When confronted with fate, Susie laughs it off. She won't let it happen. Wheras someone like Noelle would try and accept it for what it is, most likely, Susie outright refuses to play by the rules.
And this gets us back into Rude Buster. Rude Buster is important. It's important enough to be the name of the battle theme, it's important enough to be what symbolizes Susie most directly in the prophecy.
I believe that Rude Buster, and what it represents, is why Gaster chose Susie.
Noelle might, in some sense, have "hope crossed on her heart". But it'd be passive hope. Wistful hope.
Susie has active hope. With every fiber of her being, she has that hope.
She inspires that hope in others. It is, as Ralsei puts it, infectious.
She infects herself with hope, and grows it.
She infects Ralsei with hope.
She gives Tenna hope.
And, though this is more of a stretch, she even, indirectly, infects Seam with hope.
Remember that the only reason we could even potentially defeat The Knight is through Susie's perseverance, and Susie has to defeat Gerson, (who Seam is talking about here) on her own.
Remember what Gerson told us.
Susie has the White Pen, that can draw over the dark pages of fate, known as Hope.
I believe that Gaster picked up his own pen, to transform Deltarune into his deltarune, one where Susie steps up to bat as the second hero of prophecy...
...So that Susie could, in turn, pick up her own white pen, and write a new ending. Chapter 7.
A retelling of a retelling.
The words on the wall called her a hero. Maybe that's not what they were ""supposed"" to mean. But, does it even matter? Through her grit and determination, it won't make a difference. She may not have been intended to be the second hero, but, she is, angel damnit, and the universe is just going to have to accept it.
She may not have been chosen by The Angel, or whatever the hell wrote that prophecy, but she was chosen by one Wing Gaster, who considers her Very, Very Wonderful.
She wields the White Pen to draw all over fate.
And, of course, that white pen has a name.
"Rude Buster".
When the hands of fate draw near, you can always count on a good ol' Susie Rude Buster to persevere through anything.