A very common DELTARUNE discussion topic is when exactly The Cyber World was created.
Some argue it was made between chapters overnight, some argue that it must've been made after Noelle and Berdly arrived.
I am very much in the camp that the Fountain must have been made at some point during the afternoon/morning of Chapter 2- After school had ended.
I realized after typing out my conclusion that I actually should probably establish Closet Knight first, because I'm not entirely sure how familiar the wider fandom is with it.
Behold, the Closet in question:
(screenshot courtesy of this ancient reddit post )
I feel like the only reasonable explanation for this flavor text is that The Knight hid in this closet- something that only makes sense if the Fountain was created during the day.
It has been argued by some that this actually refers to GIGA Queen, or that this is referring to Kris potentially hiding Berdly's body in the weird route. But I don't really think either of those make sense.
As for GIGA Queen... I don't really think that makes sense. The Mansion is not this closet- the cabinet on the other side of the room is seemingly the mansion, with its backup devices (servers) and mice.
I actually feel like the closet is completely unaccounted for in the Dark World. Which makes its inclusion all the more interesting- why add this closet here? Why make it *open*? Why is it ajar? Surely it would've been easier to just draw a closed door?
As for Berdly's body... I don't think the body would need to be hidden? I feel like the sweepstakes heavily, heavily implies that Lightners still turn to dust:
Spamton going out of his way to specify that the Jar is what would happen if "I died just like I became a real boy and became graveyard dust" to me, at least, basically confirms that lightner monsters turn to dust like in Undertale- What else could spamton possibly mean by "dying just like a real boy"?
So, I don't really think the body would need to be particularly hidden in this sense- and, even if we assume this is the case, why does the closet specify large person?
I think it makes sense if we assume The Knight used the closet- it specifies "A large person could easily fit in here" so that we don't, say, try and use the apparent size of the closet to rule out candidates. If a large person could easily fit, then basically anyone could fit in the closet with ease.
There are ... several, other details that you can rope into this sort of discussion, which I'm not particularly going to go over, but, as a brief overview:
Queen mentions that The Knight created the Dark World "Today", which is odd phrasing if it happened overnight
Noelle and Berdly's books being on the table (something that is acknowledged with dialog) is odd if the room was already a Dark World when they arrived
Queen remarking "Hell Of A Study Session" would suggest the Study Session did, in fact, begin.
Ralsei saying he "Sensed a dark presence and hurried over" suggests the Dark Presence in question is at least somewhat recent.
So, in my eyes, the timeline looks something like this:
The Knight is in the Computer Lab, preparing to make a Dark Fountain. They have reasoned this is a good location, as the internet outage makes it highly unlikely anyone would actually want to use the Computer Lab. All they have to do is lock the door behind them, and people will assume the lights are off and that it's simply closed.
Suddenly, Noelle and Berdly enter the Library. The Knight, in panic, hides away in the Closet, hoping they'll leave.
Noelle and Berdly begin their study session- it becomes increasingly obvious that they are here for the long haul, and are not going to leave any time soon.
The Knight, now stuck in the closet, decides that the best they can do to salvage this situation is to make the Dark Fountain here and now, bringing Noelle and Berdly into the Dark World with them.
As an aside, there are two details relevant for this particular point:
Due to the smoke filling the room, it's impossible for Noelle and Berdly to see what's happening:
2) Noelle freezes in fear and confusion:
And, I heavily doubt that Berdly would abandon Noelle in her time of need here.
Therefore, neither Noelle nor Berdly see what's actually happening, nor do they escape the room in time.
Continuing,
The Knight, Berdly, and Noelle enter the Dark World. The Knight begins speaking to Queen, trying to coach her on what to do, introducing itself as "The Roaring Knight", and getting as far as explaining how they made the Dark World with Determination before being forced to flee before they're spotted and identified.
The Knight flees the Dark World through unknown means, forgetting to lock the door behind them in their hurry.
Almost immediately after this, as if by divine plot intervention, an Annoying Dog starts doing donuts outside, causing a massively convenient Traffic Jam that prevents the Delta Warriors from pursuing the Knight or gaining further insight.
This all gets us as far as Closet Knight, which is nothing new, but often debated.
However, the point of this post is that I'd actually like to go a step further. I believe it is possible that The Knight created the Cyber World when Berdly was in the room... but before Noelle had actually arrived.
I propose: The Berdly Conspiracy.
This has several implications, for instance, it explains why Berdly was not in Cyber Field at the start of the chapter- He "spawned" near the Mansion, since he was already at his desk.
It also kind of recontextualizes why Queen thinks Berdly is so annoying- The Knight left when he showed up. She might hold it against him.
But, the most important implication, would be that Berdly has actually seen The Knight.
Why hasn't he mentioned this? Remember, Berdly wasn't there when Queen monologued about The Knight, and by the time we seal the fountain, he's under the impression that this is all a dream. There was never really a moment where he would've been aware that the information he had was relevant or at all important and had an opportunity to share it- from his perspective, he saw Queen speaking to someone, who left in a hurry.
I can see it now... There will be a scene in, like, Chapter 5, where the Fun Gang is trying to figure out who The Knight is, and what their plans are, and Berdly has some incredibly important insight or information, and susie's all like, "YOU DOLT WHY DIDN'T YOU TELL US THIS!?!?!?!" And Berdly is just like "Well, YOU told me that it was just a dream, Susan!! Why would I bring up something that I saw in my dream!?" and it's hilarious. I see the vision.
This, obviously, is not foolproof- you still have the question of why Berdly and Noelle ended up at their desks at the end of Chapter 2, and also why Noelle is so easy to accept that it was a dream. (It is often argued that surely if the room were already dark when they arrived, they wouldn't be so easy to accept they 'fell asleep' if they can't even remember getting inside?)
But I find it oddly compelling, and an interesting school of thought for consideration.