hey, is there any official lore for the Cursed Vault? like why they exist, who is/are responsible for them, since when and why they're in Hogwarts, why they are cursed, why the curses (ice, boggarts, sleepwalking, etcetera) are specifically those, or why they need Legilimens to open some of them?
as far as i know JC never explained the Cursed Vaults and its history, which is a shame. like i'd love to know what's the science behind everything.
This is the idea I’m using in my series “Secrets and Riddles”, but it’s basically another theory. And since the series is not widely popular, I decided to post this in my more usual theory format to hopefully reach more people – because, not to brag or anything, I think I finally cracked it. Or at least I managed to answer a lot of questions.
Also, yeah, that means that this post is sort of a spoiler for the fanfic, especially the recent chapter 6. Just so you know.
A while ago, I also made an analysis on Rakepick’s role in the story and her connection with Jacob, which is kind of related to all of that, so I recommend checking it HERE. But that being said, I’ll focus mostly on the Cursed Vaults themselves this time.
Oh, and I’m kind of gonna ignore the Sunken Vault as we’ve seen it in Y6Ch42. I mean, I still believe that either it was fake, or we just didn’t really complete it entirely, or the writers simply screwed up at that point. Like, you can’t tell me that the final Vault was always supposed to be protected by just freaking rocks…
But without further ado, let’s get on with it.
The requirements to reach the final Cursed Vault
First of all, I’m pretty sure that the Vaults have to be open in a certain order. It explains why we’re finding in each column the clues only to the next Vault. I mean, we could get everything in the Vault of Ice and just go to whichever we figure out first. Moreover, we know that Jacob was opening the Vaults in the very same order as we.
Jacob was expelled shortly after Duncan’s death, so he couldn’t enter the Vault of Ice and the Vault of Fear then, because we know he was still at school when dealing with them. Moreover, in one of his notebook’s, he wrote:
“(…) the next vault” implies that he had to have some vault already behind him, and by elimination, it must’ve been the Vault of Ice, so the one which starts it all.
My second assumption in this theory is that you have to go through all the Vaults to be able to enter/open the final one. It’d explain why R made Jacob deal with all the Vaults before the Portrait Vault. I mean, we’re supposed to believe that they cared only about his Legilimency skills to open the Legilimency door, right? But if that was the case, they actually should’ve tried to keep him away from the previous Vaults, so he wouldn’t get hurt or something.
The third requirement is the one I talked quite a bit about on my blog already, and it’s about experiencing the loss. I always compare it to seeing Thestrals. The difference here is that I believe that you don’t necessarily have to see the moment of death as it’s very possible that Jacob wasn’t with Duncan when the explosion occurred. Moreover, I don’t think it even has to be death – I assume it’s mainly R’s interpretation. And yeah, that would mean that they planned Duncan’s death from the beginning, and that’s why they were so willing to risk his life with an extra-explosive potion. For MC, the loss would be of course about Rowan. What’s important here is that it explains why R insisted on killing one of our friends, despite the fact that they never gave us a reason for that (like, they didn’t say if it was punishment or what).
The mechanism behind the Cursed Vaults
Here, we’re stepping into the territory of speculations without as many proofs, but I think it really works overall.
All right, so imagine that the Cursed Vaults are like a chain around the treasure in the final Cursed Vault. At the very beginning, there’s a lock on the first link of the chain. Once you break the lock (in that case: defeat the Ice Knight), the lock moves to the second link: the Vault of Fear. Here, you break the lock either by defeating the Boss Boggart or by opening the column with a broken wand. Next, the lock moves to the Forest Vault where you break it by opening the column with the arrow. The lock moves to the Portrait Vault where you break it by defeating the dragon, and the lock moves to the Sunken Vault. I call this process the cycle.
Now, I assume that you have only one attempt at breaking the lock at each link. Otherwise, the cycle resets. This means that, for example, if you enter the Vault of Fear but fail to defeat the Boss Boggart, the cycle resets, and you have to go back to the Vault of Ice etc. Why it’s important? Mostly because of the note we found in the Weird Sisters TLSQ.
If R previously entered the Sunken Vault without the key, in my theory, it’d mean that the cycle reset – and so it’d explain why MC had to start from the Vault of Ice again at the beginning of the game. I doubt the key on its own would break the lock entirely, but the Sunken Vault, as the final one, might have a more sensitive security system.
On top of that, I concluded that once you successfully break the lock on one Vault, the Vault itself becomes kind of “inactive”. Remember when we were searching for Scabbers, and it led us to the Icy Corridor? It’d explain why the cursed ice was… different then:
Also, I know it’s a bit questionable how much of canon TLSQs are, but it’d potentially explain how Rakepick revived the Ice Knight in the “Call to Knighthood” TLSQ without any consequences (like reactivating the curse):
By the way, I’m still fascinated by the fact that Rakepick just… revived the Ice Knight. Like, how powerful is that woman? Also, of course she had to be extra like that in comparison to other professors...
Anyway, the point is that you can kind of “play” freely with the Vaults, as long as the lock moved to the next one. I also assumed here that the columns remain open – because technically, we’ve never seen whether or not they close after MC leaves the Vault. And it’s pretty important for the next part.
What the hell was the deal with all the clues?
I’ll start by saying that I absolutely don’t expect that Jam City will address it in the future. But guess what? I don’t care because I think I’m right either way. So, who and how placed the clues?
I believe that Jacob was responsible for the clues, probably along with Rakepick. However, I also assume that they only prepared them, and it was Dumbledore who placed them in the columns. It’d explain the scene we’ve seen during our Legilimency lesson with the Headmaster (Y5Ch19):
Also, in the Vault of Fear, we found the arrow and the Forest’s Map:
Now, this one is admittedly not my original idea - I remember reading it ages ago on Reddit (I believe). But I loved this theory ever since that this “R” was not a reference to R but to Rakepick. You know, as a hint that she’ll help us with the Forest Vault. And it actually makes a lot of sense, because where was the missing arrowhead? Buried.
The only way is to bury it because Rakepick has Sickleworth, and finding buried treasures is no problem for him. For anyone who doesn’t have a Niffler, or rather so well-trained Niffler, it’d be probably much harder. And look at that, we did use Sickleworth to find the arrowhead! That being said, I also always saw one big flaw in this theory…
See, I suspected for the longest time that Jacob had something to do with the clues, but it didn’t make much sense that he’d put that “R” on the map. He knew about R and that they’re called R – he had to know that it’d be confusing. HOWEVER, if it was Dumbledore placing the clues in the columns, perhaps it was him who put that “R” in the last moment to hint to Rakepick. I mean, if you ask me, it’s totally possible that Dumbledore at that point was aware that someone threatens Jacob, yet he didn’t know they’re called R. Jacob might’ve hidden that information in fear that if he tells Dumbledore too much, R will find out and they’ll punish him. I don’t know, maybe it’s just me, but I actually find it pretty amusing to think that Dumbledore might’ve been a total scumbag who confused everyone with his one small addition, when for once, he genuinely thought he’s being helpful. Like, we know he’s a manipulative bastard, but in this case, he really could’ve screwed up by accident.
All right, but let’s move on. In the Forest Vault, we found a portrait with a dragon (which doesn’t need explanation) and a tiny sweater. And this damn sweater bothered me for so long. Like, not only it was totally abandoned by the writers, but no matter how I looked at it, it didn’t really make sense. All I had was a connection to House-Elves. I mean, it basically is a House-Elf size, and we had Patty hinting on something with House-Elves at the end of Y4:
Interestingly, we had some mentions of House-Elves even earlier in Y4. For example, it was one of the first things Rakepick did in Y4Ch1:
And then, in Y4Ch14:
But I couldn’t think of any connection between House-Elves and Hogsmeade. Like, was there a removed plot where the entrance to the Portrait Vault was through Hogsmeade, and not the Portkey? Was the Portkey supposed to work only in Hogsmeade?
And then, it hit me just recently: Pitts was supposed to lead us to Aberforth in the Hog’s Head Inn, who ultimately led us to the discovery about Legilimency. Because look, the way it actually happened in the game was simply… too random.
So, we had that whole plot with Rakepick figuring out the truth about Pettigrew. At one point (Y5Ch17), when we were interrogating Fletcher, he admitted that he left the Marauder’s Map for someone in front of the Hog’s Head Inn. Therefore, Rakepick sent us to check it out, and then we met Aberforth.
… and then we learnt about Legilimency. But like I said, the whole situation was just… very random, in my opinion. Moreover, I believe there was something more planned with that letter because when you think about it, it’s very strange, too. Like, what was in that letter? Was it only: “Come to my office. – A.D.”? Then why writing a letter at all? Aberforth could’ve simply told us this much. And if there was anything more, what was it? And why we never learnt it? I mean, MC always reads the notes/letters aloud. So, what’s the deal with that?
And so, I’m pretty sure that a tiny sweater was supposed to lead us to Pitts, who was supposed to somehow lead us to Aberforth. And you know what’s the best about this idea? There was once a side quest with Rita Skeeter, “Rita Returns”. It’s currently pulled out from the game, sadly, but we had there two opportunities to learn some information from Rita:
So yeah, I feel pretty confident about it.
Now, one last thing I want to discuss. In the Portrait Vault, we found a Trident and a Portkey back to Hogwarts.
A Trident doesn’t need much explanation, but there’s one interesting detail about a Portkey. I mean, other than the fact that it’s awfully convenient. But when we were asking House-Elves about the vault portrait in Y5Ch12, one of them said this:
And here, I’m thinking of two possibilities:
The House-Elf talked about Rakepick who already knew that the kids are gonna find the Portkey back to Hogwarts (because she knew about the clues).
The House-Elf was talking about the situation from years ago when the clues were placed. Obviously, Rakepick wasn’t a teacher back then. They wouldn’t call Dumbledore “a teacher” either. But you know who was a teacher at the time? Snape.
Here’s what I’m thinking. I assume that Jacob and Rakepick lost the vault portrait at some point, and that’s why MC had to actually search for it in Y5. Now, if that’s the case, Dumbledore probably couldn’t access the Portrait Vault, because I imagine that you need the Portkey for that. However, since Rakepick was there already to break the curse, she technically should be able to return there by Apparition, in order to place the clues. But there’s one more obstacle: the Legilimency door. And sure, it’s possible that they stay open after the curse is broken as well - just like the column. But if not, she’d also need a Legilimens. And look at that! It happens that Snape is a Legilimens! Why wouldn’t she Apparate with Dumbledore, though? Well, I imagine that they were short on time, and he was simply busy with other clues.
To sum up
So, to put it short. Jacob and Rakepick found out that R is planning to enter the Sunken Vault without the key. They knew it would reset the cycle of the Cursed Vaults. They decided to use it, and because the columns were still open, they had to act quickly to place the clues in there. Once R entered the Sunken Vault, the cycle reset and the columns closed, waiting for MC to find the clues inside.
And that’s it! As I said, I doubt Jam City will care to explain any of that, but I’m gonna be honest – I feel really good about this theory.
Every now and then I’m going back to the thought that the final Cursed Vault was constructed to trap a conscious being, and I wonder what it could be exactly. And I’m not gonna lie, I quite like the idea of it being Sekhmet – or rather her equivalent. If you don’t know, Sekhmet is an Egyptian goddess and one of the goddesses associated with the Eye of Ra – which is of course Rakepick’s pin.
Now, I do fancy the idea of Patricia being somehow connected with the Cursed Vaults, even if only metaphorically. But more importantly, it could work pretty nicely story-wise. You see, the thing about Sekhmet is that she’s about duality:
But there’s also one particularly interesting myth about her:
If you think about it, it could have some reflection in the Cursed Vaults story. Some ancient being who wasn’t inherently evil went rogue and couldn’t be tamed. The difference would be that the wizards at that time didn’t come up with the solution of tricking the being to bring it back on a good side, and so they decided to simply trap it. The only thing that bugged me is that Sekhmet is an Egyptian goddess – so using her in specific would be kind of odd. Therefore, I was trying to find a Celtic equivalent for her. And you know what? I found something.
It’s not a perfect match, but there’s definitely some similarity. And… “a red cape and hood”, you say? Just like a certain evil organisation uses? 👀 HMMM.
There’s also another option:
… which is actually more fitting in symbolism, and the crow could explain Black Quills.
Anyway, I don’t really have conclusions here, but I’d say it’s something one could work with.
Source: Wikipedia and this site.
P.S. Way less seriously, but I once had that stupid idea, that it all started with the Hanged Man from The Arcana because, y’know, he’s a humanoid raven. And if this doesn’t explain Black Quills, I don’t know what would.
Hi I hope I'm not bothering you but recently I'm becoming more aware of the inconsistencies in the plot of HPHM and it's driving me crazy. Starting with the Cursed Vaults themselves. Every year, at the beginning of the Hogwarts term, we are told that the Vault has been "opened" and so begins the curse of the year. But does that mean that someone opens them and then they have to be closed? Would it mean that someone already knows where they are and they are forcing MC to go behind and close them?
Of course you’re not bothering me!
I see what you’re saying, though I think those aren’t even inconsistences, but rather simply lack of information. But in general – yes, I believe that that’s what happens. Someone “opens” the Vaults and forces MC to go behind them. Moreover, I believe that it was pretty much the same with Jacob and that someone is R, meaning that they basically know ahead where each Vault is. Let’s try to go through all of that.
First of all, let’s talk about R. We know that they’re an international organisation, meaning that they have to exist for quite some time to develop this much. Now, I personally like to think that the Cursed Vaults are just one of their focus, but I also believe it’s quite possible they originated from the group who created the Cursed Vaults. What I’m trying to say is that either way, they had time to do their research and whatnot. The fact that there was no activity around the Vaults before Jacob is actually the reason why I believe that the siblings are needed to open them (or at least the final vault). The fact that they put Jacob through all the vaults, on the other hand, is what made me came up with the idea that you have to go through all of them to obtain the final treasure (whatever it is).
And yes, it does seem like R forced Jacob to search for the Cursed Vaults. Duncan told us that they were blackmailing him by threatening his loved ones, but it was at the time of the Forest Vault already. Before that, we had this note in Jacob’s notebook:
I believe that R had to know that Jacob would feel responsible for students getting hurt. Like, it seems that it was Jacob’s thing as in the “Egg Hunt” SQ, Alistair also told us:
(By the way, that’s one of the reasons why I don’t trust vault!Jacob at all. He never showed any concern about people getting hurt because of the curses…)
Of course, when we move to MC, we kind of have a problem: R didn’t want MC to search for the Cursed Vaults at first. Well, yes. But I assume that they did want to get to the final vault either way. Unfortunately for them, for some reason, they had to start from the Vault of Ice again. And I imagine that you have to activate the curse to break it, move to the next vault, and eventually reach the final one. So, technically, they didn’t want to force MC to anything, but they basically had to do this. Does it make sense so far? Interestingly, notice that only in Y5 – when R wanted MC to go after the Vaults for sure – MC was affected by the curse more personally. It was Bea who got trapped, our friend’s sister. Perhaps it wasn’t a coincidence at all then?
Now, another important question here is what exactly that first “opening” involves. Because the game specifically calls it “tampering”:
… but it never explains how it’s done. Like, how the curses are being activated? I thought that maybe you have to enter part of the vault, but not open the column? Like, in the case of the Vault of Ice, it’d be entering the Icy Corridor leading to the Snowflake Door. But then, we run into a problem with the Vault of Fear. You see, you need the book to open the passage to that Vault in the Restricted Section. The book which was in the column in the Vault of Ice, and then (as far as we know), MC had it all the time in their possession. So, how the Boggarts would get activated after the Vault of Ice without the book?
I also had another idea that each Vault has kind of an outside mechanism activating its curse. One interesting thing we learnt at the beginning of Y2 was this:
I imagine that “last time” has to refer to Jacob’s time. And I keep wondering why in both cases the cursed ice was spreading from that specific room. Perhaps there was something inside of it, but we just never examined it properly? In the case of the Portrait Vault, that activating mechanism could be the portrait which trapped Beatrice. We were told that someone looking like the Red Cloak was doing something with portraits there:
We didn’t get much to speculate about other Vaults, though.
I hope it cleared some things up. Of course, it’s mostly my speculations based on that little information we got. But I think it kind of adds up, y’know? Though as I said, we just… don’t know enough. And it’s really frustrating.
Do you think that the organization name is really R? I mean... Is such a very poor name. At first I kept thinking that R was the name given due to the letters MC found of them signed as R, but then there were adults like Moody, Rakepick, etc. calling them R as well. I don't know, it just keeps smelling fishy for me. Just R? Is not intimidating, no nothing. Do you think that JC just took it so would be weird for change it now? Or will reveal their original name soon? I'd love to.
I mean, I do think it’s an initial for something. Although I believe it’s being held a secret for so long for a reason – both from the writers’ point of view, but also from the story’s point of view. In the first case, they obviously want to keep the audience speculating and whatnot. However, I can also see some reasons why R themselves (as the organisation) don’t want to reveal it.
All right, but what would it stand for, to begin with? I was never really convinced that it’s an initial of real name or last name. I mean, if you’re sending secret messages, signing them with your own initials wouldn’t be… very smart. In general, I’d say that you’re using your initials if: 1) you don’t feel like writing full names, 2) you know that the receiver will know who you are, but you don’t necessarily want anyone else to know. For example, let’s look at R.A.B. situation from the Half-Blood Prince. Voldemort would probably know that it was left by Regulus, but for Harry (and for us) it was a mystery. So, applying this to R, it could suggest that Jacob might’ve known who R was – but he didn’t:
This message was written in Jacob’s notebook which additionally was in a code. If Jacob knew what “R” stands for, there was no reason he wouldn’t use it there. Similarly, Duncan was also always referring to them as “R”.
My point is that they definitely wanted to keep their identity a secret. So… why would they use any name for that?
Personally, I believe that “R” comes from a word – which would make it harder to figure out who hides behind it. Like, a word describing their philosophy, for example. When I wrote “The Untold Story of the Cursed Vaults”, I decided on the word Remedium which is Latin for a cure, medicine. See, my theory is that R originated from a group responsible for creating the Cursed Vaults. There were also hints in the story that the Vaults were created to imprison something dangerous, and in that case, R would in a way cure the wizarding world of that threat. Of course, that’s just my idea, but I feel that the true answer follows a similar logic. I don’t know, perhaps it’s Resurrection instead? After all, R believed that they were on a way to immortality…
Either way, even if R wasn’t directly involved with the Vaults’ creation, the thing is that they have to exist for quite long. We learnt from Moody at the beginning of Y6 that R works worldwide, and to build an organisation like that – and to do it in a secret – you definitely need time. Frankly, I wouldn’t say that centuries are an exaggeration. So, if they were present for so long… what if there is some historical evidence of that?
Here’s what I’m thinking. There’s that one HoM class about the Wizards' Council which was eventually replaced by the Ministry of Magic. What if before that, the Wizards’ Council was created from Remedium (I’ll keep using this name as a placeholder)? If R would let anyone know that their real name is “Remedium”, they’d risk that someone would make the connection to Remedium from the past. This, on the other hand, could lead to the further investigation and discovery that the members of R are still among the employees of the present Ministry of Magic. That’s just an example, of course, but my point is that maybe a true name could expose too much. Therefore, only the highest-ranking members of R might have this knowledge. Both Moody and Rakepick might simply not know that.
That being said, I agree that it’d be great to finally learn the original name. I do hope it’ll happen at some point. However, I’m afraid it won’t be any time soon, seeing how Jam City is stretching everything out as much as possible.
One of the things I miss the most in Hogwarts Mystery is the proper lore behind the Cursed Vaults. It’s the reason why I came up with my own idea for their symbol over a year ago. Now, if I’m being honest, I kind of doubt at this point that the game will deliver a proper explanation in that matter, so… I attempted to create something myself again.
There was a time when magic thrived in the world, when wizards and witches were growing strong. But with great potential comes also the danger. And so, as one of them became nearly impossible to control, it was settled to lock it up for no one to ever abuse it. The greatest ones were chosen to hold that secret and keep it safe. Four of them established their School of Witchcraft and Wizardry at the time, the place intended to gather brilliant minds, shape young talents, and provide protection. Needless to say, it was the most proper location to exploit. However, the walls of the castle and the insiders’ watchful eyes weren’t enough. That’s why the Cursed Vaults were created. Each Founder was responsible for creating one Vault and each of them represented what they valued the most.
Ambitious Slytherin who wielded the power over the Ice Knight set a guard for the First Vault. Gryffindor, who treasured courage above all, reassured that no timid soul would face the Second Vault. The Third Vault held the threat of death, but fair Hufflepuff placed it away in the Dark Forest, so the students would be safe. Finally, wise Ravenclaw designed the most difficult obstacle in the Fourth Vault as it’s the hardest to face the secrets hidden in depths of your heart. Then, they created the Fifth and Final Vault together. And only the one who conquered all the previous ones and who knows the meaning of the real loss can earn what lies within. Each Vault had the sealed curse which would punish any intruder trying to penetrate its inside. The curses had a secondary role as well – they would inform that the balance was disturbed and chastise those who let that happen.
When the creation was completed, four families were chosen to keep the keys to the Cursed Vaults: the Knowledge, the Book, the Arrow, and the Portrait. And four more families were appointed to guard Hogwarts and people living there in the situation where one of the curses would be released. Both the Key Keepers and the Guardians formed the Eight Branches. In addition to that, two more families were involved - the Core, connected with the Final Vault. The Core consisted of the Key and the Guardian who was devoted entirely to protecting the Key itself. The choice of them was special because of the importance they were about to carry. The Key possessed the natural ability to read human nature to help them stay safe from the wrongful influence. The Key’s Guardian had exceptional power to help them do their duty.
The Eight Branches and the Core formed a bigger group, and they called themselves Remedium. They kept the Cursed Vaults at peace for centuries, and they passed their secrets through generations, maintaining the strict structure. Nevertheless, time changes everything. And so, there were wizards who didn’t want to be burdened with such responsibilities any longer, whether it was caused by selfishness or fear. They never revealed any information to their children, cutting off the whole Branch. Other families left to different countries where the Cursed Vaults became more and more irrelevant with each passing decade. Some of them would die off eventually, either naturally or in unfortunate events. In the end, corruption consumed the others. The knowledge can be overwhelming, especially when it can lead one to something far more powerful. The remaining members of Remedium succumbed to the promise of the treasure lying in the Cursed Vaults. Still, there were a few of them who wanted to stay true to their origin, but because they were in minority, they were considered traitors and called the Cabal.
The schism weakened both sides. They worked on growing back in strength and becoming even more. After years of their conflict occurring in the shadows of the wizarding world, the Cabal decided that the ultimate way to stop Remedium and keep the Cursed Vaults safe is to eliminate the Key Keepers and the Guardians. In particular, they needed to annihilate the Core. Little did they know, that it’d be the hardest part. Nobody heard about the Key or the Key’s Guardian in forever, it seemed like they were among the ones who ceased to exist. And without them, the Cursed Vaults were untouchable.
Until the day when one curious boy started reading a peculiar book, sentencing himself to the life of a nightmare where one ancient organisation wants to use him for their own gain and another wants to kill him.
_____
All the ideas (except the name Remedium) are based on information from the game, including the House sigils from” Nearly Headless Nick” SQ and the mention of the Eight Branches book from “Sleep Walker” SQ – both of which are currently “temporarily” removed. Go figure. Anyway, you could say that it’s kind of “a novelisation” of the theory (which surprisingly was not that easy to write…).
Also, I wouldn’t dare to compare it to the opening from The Lord of the Rings, but I do imagine it being narrated by Cate Blanchett, and, um... it’s pretty cool if I say so myself.
What do you think is the treasure inside of the final Vault? For a while I thought it might be the Sorcerer's Stone, but today it occurred to me that it might be a Deathly Hallow, like the Elder Wand.
To be honest, I hope it’s neither.
I know that HPHM is basically an alternate timeline, but personally, I’d like it to stay as true to the books as possible. And if any of the Deathly Hallows is in the final Vault, it contradicts the original canon quite seriously. Both the Elder Wand and the Invisibility Cloak should’ve been currently in Dumbledore’s possession. He won the Wand from Grindelwald in 1945, and the Cloak was passed by in the Potter family for generations. In the meantime, the Resurrection Stone belonged to the Gaunt family and then was turned into Voldemort’s Horcrux. Now, it is possible that one of the Hallows is indeed in the final Vault (meaning that we were “lied to” in the books) – I just don’t see a good reason to intervene in the source material so much when it comes to something so important. Yes, the current writers make stupid decisions. But I want to believe that the original team was smarter, and the ending will follow their plan, even if getting there will be rather bumpy.
The Philosopher’s Stone would make more sense, in my opinion. And I actually discussed this idea in the past, so I hope you don’t mind if I just link it: CLICK.
Still, I’d like it the most if the “treasure” was something entirely unique, just like the Cursed Vaults themselves were created purely for that story. Now, we don’t have much to go by, but if we want to believe in information from the “Nearly Headless Nick” SQ, we do have something:
I assume that it might also mean that the Cursed Vaults were created around the same time as Hogwarts. I mean, since the vaults are on the school grounds, I think it’d be a bit odd if the castle was built first, and only then something would appear there that couldn’t be moved.
As for what it could be exactly… Hm, I recall a similar story about the Veil in the Department of Mysteries: that the Ministry was actually built around the Veil. I’m just not certain now if it was a fan theory or a “real” rumour existing in the universe (or rather on Pottermore or something). But either way, perhaps it could be something like that? Let’s say that if the Veil in the Ministry allows you to go to the afterlife (so it basically kills you), maybe the Vaults holds the Veil allowing you to go from the afterlife? It surely would be considered more dangerous and therefore require better protection.
Another thought: maybe it’s a kind of the prototype of the Pensieve? Just way more powerful in some way, and the Pensieves used in modern times are merely an imitation of that.
I also quite like the idea that the final Vault holds some kind of entity, more or less conscious. Although, it fits less the assumption that it can’t be moved. Unless... the entity is trapped in something, and the final Vault holds that “something”.
