Hypothetical Deltarune/Sagan 4 crossover. Perfect pacifist route described. I might elaborate more / turn this into a legitimate fic later, but I have never really done dialogue for dr's characters, so...
There is a large room that contains nothing but a hard drive containing a backup of the Sagan 4 wiki at the end of Week 26. There is a door in the southwest. A fountain is opened in the northeastern part of the room. With nothing else to work with, the world that forms is a rough copy of Sagan 4's week 26 ecosystem with darkners based on various extant species. Kris and Susie end up here somehow, and Ralsei is close behind.
Lancer and others aren't here because I forgot about them, but they;'re also just not in Kris's pocket.
Click to expand
After landing in the ocean, the party ends up on Fermi Island, where the weirdness of this particular dark world starts to set in. The world generated is so large that the fountain--located in Drake--isn't even visible, and there is no sign of any clear main antagonist. Nobody here even wants to fight. Some additional weirdness is, of course, visible to a Sagan 4 fan; this is obviously not Sagan 4 1:1, as the fauna can talk and there's a multicultural potluck going on in Fermi Tundra. With nothing to do here, the party boards a kind seashrog's row-nest (???????????) and makes their way to the supercontinent.
Things start to get more interesting on the supercontinent, but it's still nothing to do with the fountain. Ralsei would probably try to get Kris and Susie to focus on finding it, after all they can't just leave it open, but how can they leave? How can the player? There's a gang of argusraptor-themed darkners bullying everyone. Yeah, dealing with that won't get them any closer to closing the fountain, but boy can you get a lot of recruits here. Susie, obviously an expert in bullies, wrestles the biggest meanest argusraptor and wins as a sparing tactic.
By this point, they've been in the dark world all day and there's no sign of the fountain, though some shrog on the beach might've mentioned seeing "something like that" while up north. Susie is hungry. Kris is too but can't say so. They buy 2 whole haglox steaks or something from a twineshrog shopkeeper and Susie eats both of them, only to remember afterwards that food in the dark world doesn't really satisfy hunger.
There's no option but to look for the fountain before everyone starves to death, but before they leave the supercontinent the party has a strange encounter with something that hints at the nature of this world as a wiki: a darkner based on the wiki layout. Sparing involves hitting the random page button a bunch of times, which spawns some familiar enemies to spare, but a lot of unfamiliar ones and "broken pages" too. After doing this several times, the wiki layout gets annoyed and tells the party to use the search function to "find what they're looking for". There are many options for searches, acting like a more controlled version of the random page button, at some point Ralsei searches for the dark fountain and finds out where it is, but after all options are exhausted the wiki layout still isn't satisfied. Susie gets annoyed and searches complete gibberish, which gets interpreted as a misspelling of "Chimlopzock". The wiki layout says they don't have that. (Susie, making that angry toothy face: "Then why'd ya correct me!?")
Kris tells the wiki layout that they found what they were looking for, ending the battle instantly. Susie and Ralsei are surprised. Susie angrily demands to know why Kris didn't just do that in the first place. It wasn't even an option in the first place. Kris has no answer and Susie is pissed off that they all just wasted so much time on that. Ralsei intervenes and suggests they move on, since fighting each other won't get them anywhere.
Leaving the supercontinent with that kind seashrog again, the party is off to Barlowe. Kris and Susie are both hungry an tired. The kind seashrog offers them his food stores, but dark food is nothing to a lightner. It must be night back home, they've been here so long that Kris and Susie end up falling asleep. (Does Ralsei sleep? I have no idea) Falling asleep hungry, waking up hungry, there's a pirate waxface on Oz Temperate Beach that wants to eat them. Kris--they barely even eat, you know Toriel doesn't seem to feed them much at all--is basically useless, Susie's more functional and that nice seashrog joins the party for this battle (when down, he becomes a broken page image). "Kris" (really the player) tells them what to do while lying on the floor, they just kinda accept that. Not possible to spare directly, the pirate has to be tired out and pacified. Kris is eventually able to get up, but being weak from long-term malnourishment and not eating or drinking anything real in over 24 hours, they generally aren't doing too good, and Ralsei worries that if they don't find the fountain soon Kris won't be able to close it. Now in a rush, the party basically skips Barlowe and continues north.
Unfortunately, they do not end up in Drake, ocean currents take them to Maineiac. The wiki layout is back. Kris is not in a state to do much of anything. Susie points out that this is a wiki--like wikipedia, right? She's probably vandalized a wiki before. Anyone can edit it, maybe they can find their page and edit their location somehow. The fountain is in Drake, so they just have to edit their wiki page to say that's where they are right now. Unfortunately, the Sagan 4 Wiki does not allow unverified users to edit it. But it's on their user pages, so actually, they can. Ralsei is against vandalizing the wiki, so Susie does it. She's bad at editing and manages to create a bridge of broken code. It works, let's go already.
So they finally get to Drake, and there's finally some actual relevant story meat. This is a world forged by the dreams of over 100 lightners, who used their great power to create and destroy life at will for 165 generations, but they're in a side timeline where one of those lightners, using great power to will a new timeline into existence, took them to this room and left them behind for unknown reasons. (Why is there a hard drive in the middle of an empty room?) They had waited and hoped for their return, as while their creators could be destructive they were also necessary for the creation of new life, but nobody came. But in Drake, away from the eyes of most in this world, the Knight appeared and created the fountain, giving every creature of Sagan 4 life, and possibly even a power to forge their world like their creators did. Obviously, the way to the fountain is blocked by several creatures that do not want the fountain to be closed and are using its power to revive their ancestors who the lightners willed into destruction. There is no sole leader, there is only a mob who are very willing to fight.
Maybe Ralsei is up to dealing with this, but Susie and especially Kris are not. If this was where they landed at the start, maybe they could, but they haven't eaten real food since before they got here and they're running on empty. But maybe their new friend, the wiki layout, can help. So, the party summons all the friends they made along the way. However, the recruits are reluctant...after all, they like the freedom to forge their own path that was given to them by the Knight. But Ralsei is able to convince them that they will still have that freedom in the castle town, so they in turn help mass-recruit everyone on Drake. However, there are three who are still reluctant, all of them revived creatures...
The power of the fountain had allowed nomads, sagons, and tripodicians to return. They hate lightners, as they created them solely to die. Their revived leaders understandably distrust the party and their promises of being taken to a castle town, and it sparks a 3 on 3 battle with some severe handicaps because Kris is in no shape to fight, though Susie can fight through the distraction of hunger. It is much like the battle with King in chapter 1, except there's 3 of them; all the party can do is hold on as long as possible until they grow tired, but they don't. Kris and Susie are too tired and go down, they cannot get back up naturally after a few turns like in a normal battle, so then it's just Ralsei. He explains that he is a darkner, so they don't have any reason to hate him like they do Kris and Susie. Only Ralsei acting alone with Kris and Susie down can successfully convince them. Afterwards, Ralsei heals Kris and Susie and they can finally reach and close the fountain (though, maybe Susie's chapter 2 reluctance is carrying over...the player closes it regardless though).
The secret boss is chimpus. I've been writing all day and am too tired to write in an explanation
Since all of this was spawned from a hard drive, Kris just kinda brings the whole thing to the castle town. I'll figure out how that goes another time.