So, I know that there are tons of theories stating things like "Kris is the Knight" and "Father Alvin is the Knight" and other things along that line. But none of those people stay awake half the knight (hehe) thinking about the truth about Deltarune. After months of thinking, I think I can tell you a thing or two about the truth of Deltarune. Remember, I will have a skele-ton of theories here. (Note: Some theories I have multiple opinions on, so not ALL of this can tie together, but some parts of it will) Now first off, if Toby Fox isn't trolling us again for chapter 3, I think I know some things about the secret boss. Mike will not be the secret boss, but instead the main boss of this chapter. The real secret boss will be someone working/worked for Mike and now resides in the (as I'm calling it for now) "Film Storage Department" where all the recordings of Mike are. This person will be a cameraman that dreamed of working for Mike and being a star on the show just to find out that when he did get the job of his dreams, he was imprisoned behind the camera. Then the person that keeps interacting with other people (e.g. Spamton and Jevil) meets him and then the cameraman would start to jump into Mike's shows occasionally. Mike fires him and then he resides in that storage area. For at least one of his attacks, he will use the films of the mike shows as projectiles on the bullet board and even play the animations on the bullet board and you will need to dodge the animation's attacks. All that I know about his appearance is that he will either be a camera or hold a camera. This is everything I know about the secret boss. THERE WILL NOT BE A WEIRD/GENOCIDE ROUTE IN CHAPTER 3!!! Instead, there will be one every OTHER chapter (so in 4 and 6 and, if one of my other theories are correct, 8). I have valid reasoning for this. If you interact with the bead toy in the hospital after the snowgrave route, it says that the blue bead(s?) are missing. Then, there are two other colors, red and green. This means that there will only be 2 other weird/genocide routes. My prediction is that in chapter 4, Catti will have to kill Jockington. This is my prediction because 1: the green beads, 2: Catti and Jockington are the only other REAL pair of friends and 3: Berdly was/is one of the most popular character in Deltarune, and Jockington is canonically the most popular character. The final genocide/weird route would be to either kill Kris or the Vessel. This one I'm still in the dark about but from what I know, you (either controlling Kris or the Vessel) are the one killing people in hometown (this route is only available if you did the previous 2 weird/geno routes). After this run, chapter 7 will change entirely. So, in short, Toriel will not be killing Undyne in chapter 3. For this next one, if you've watched every theory on youtube it might be a shocker, but Gaster is the Knight. ... Kinda. You see, we created a goner in the goner_maker sequence. I will make another theory project all about Gaster. But all that you need to know now is that Gaster IS the goners. So, we are not making a vessel for US, but for Gaster. (in the Gaster theory one I will have a part for the vessel) See, because Gaster was "scattered throughout time and space" he doesn't have one, singular form, thus rendering it impossible for him to create a fountain, meaning that he had to find a vessel if he wanted to do anything. This can also explain why some people refer to the Knight and the "mysterious someone" as two separate people, because Gaster is in the vessel whenever he's the Knight and then he is referred to as someone else whenever he is in his Gaster form. Now, I'm going to (slightly) save you some time and have you search Chess Theory Deltarune on youtube and that can explain some things. BUT, I'm going to add even more. Even though the game SHOWS that it only has 7 chapters, there could be a secret eight. If you watched the "Undertale's 6th anniversary so we play Deltarune Chapter 1 for some reason", before everything starts, there was a song that, as the description says, would play as you go up a long staircase with silhouettes of all the previous chapter's bosses with the Knight at the top. This is depicted to be an endgame event. But, once you watch chess theory, you'll fond out that any pawn (pawn as in all the characters EXCEPT the bosses of each chapter) can be promoted to any other class (besides king) once they reach the END of the board. So, after we defeat the Knight, seal the last fountain, prevent the Roaring from happening, and go to sleep for chapter 7, either Kris, Susie, or Ralsei will become the knight (this could also be a Ralsei betrayal like most theorists think will happen). Chapter 8 will be the TRUE final chapter of Deltarune. I ran out of room so the rest will be in the notes and credits, continuing from the chapter eight theory above.
I actually have a couple of other theories on what can happen. First off, none of your party members become the Knight but instead (this has a tie in to the Gaster theory from earlier) with the vessel defeated, in chapter 8 the true final boss will be Gaster. The second one is that Toby will surprise us (well, everyone that hasn't seen this) with chapter 8 and it will start with the defeated Knight starting the Roaring and we have to stop the titans (also, the titans kill the Knight) from destroying everything. Wow, at this rate I'll need another project JUST to talk about all my other theories. But lets not stop here! Next up, Mettaton (A.K.A. Hapstablook) is the Knight. Think about it for about a minute. Who is the final enemy that you have to defeat before fighting Asgore in Undertale (not counting genocide)? Who has been/will be referenced over and over again in Deltarune's Dark Worlds? Who has changed very significantly from Undertale? The Neo body, Mike who (in theory) is a game show host, even (now, this could either be a reference to Undertale or the Neo body. Also, this will be part of another theory) Asriel's final boss in his game are just a few events that are referencing that. This could also figure out how the computer lab dark world was created, (note: Berdly and Noelle started studying BEFORE the dark world opened up) because ghosts can go through walls. Ok, this is all the evidence for Mtt Knight theory but I have tons of OTHER knight theories to share. For example, Berdly could be the knight. Now, this one I only have 2 solid facts, but other than that, he would just be a Bluebird of Misfortune(M) trying to win a Smart Race(B). These two facts are that 1: Berdly was in the computer lab when the 3rd dark fountain was made and 2: the knight was close to King so, if Berdly is the knight, he was trying to get close to queen. The reasoning for the first one is that he could've told Noelle that he was getting something out of the closet and then made the fountain, sat back down to get ready to study while the fountain consumed the room (this could also be reversed for the next theory, where Noelle makes the fountain). The next Knight Theory is that Rudy could be the Knight. Now, your probably thinking "But Rudy's in the hospital, how could HE be the Knight?" Well, I'm glad you asked. First off, he has an unnamed decease, likely from draining his power to create dark fountains (that he opened before the events of Deltarune). Secondly, he could secretly be using Noelle to help him finish what he started. Also, since we know that there will be a chapter in the church and Rudy said he could come to church tomorrow, he might make the next dark fountain himself while previously he just used Noelle to do it. Now, Rudy going to church on Saturday could mean one of two thing, one, chapter 3 will take place during the night of chapter 2 and then we go to church in the daytime of chapter 4, or he didn't know what day it was so he just presumed that it was Saturday. This is possible, but by "I might be well enough to go to church tomorrow" could be saying that he could be going to his funeral. Also, if he is the Knight and he is at his funeral, possibly he could have Noelle create another dark fountain to revive him with a heal prayer spell and then the two of them leave the church to go home. This theory is probably the most reasonable when you think about it. Now to tie some stuff together. Mtt/Hapstablook could be the mysterious someone that people keep talking about, seeing as he is a ghost and able to go anywhere he wants. And, like I said, Rudy made Dark Fountains in the past so, likely, caused or almost caused a roaring. But the three heroes back then died so that they could save everything. These three heroes are the residents of the ghost house, Napstablook being the kindhearted one, Mad Dummy being the violent bully, and Hapstablook being the leader. Gerson possibly also helped the trio along the way too, going as far as to sacrificing himself to save the trio from imminent death. So, the trio used their own souls to close the 3 fountains and use Gerson's soul to weaken Rudy enough to where he could never make another fountain again along with wiping the memories of the events from everyone and replacing some of them with better ones (e.g. making everyone think that Gerson died of natural causes). So eventually, the trio will have to help Kris, Susie, and Ralsei to seal the fountains. Or all these people who think that Lancer is actually the prince of darkness and the Ralsei is actually the knight are correct. Who knows, everyone could be wrong and Toby Fox is the knight (I mean, it DOES make sense, he's LITERALLY creating the fountains and Undertale has text referring to fighting the dog. Also, this is something Toby Fox would do so...) But for now, all that I said is just a theory. A game- nope, not going there. Thank you for reading and please comment on your thoughts.