Ridley64

If Ralsei is a counterpart of Asriel, something bad is gonna happen to him/he's gonna turn evil. Because by being Asriel's counterpart, he may turn into something similar to Flowey.

The track that plays during the character creation sequence is called 'another him'. So, could this be another Gaster?

During that same sequence, there is a change in font's when your character is discarded. So, that could imply that Gaster and someone else is narrating?

There may not be a good ending to Deltarune. In Undertale, you can't get the best ending if you kill even one monster. In Deltarune, you can fight as much as you want, but there is only one ending. So why expect a happy ending?

One week until Asriel comes back. The first chapter lasted one day. Possible 7 chapters?

Sans's bedroom door looks like the doors used to travel around. So, Sans could possibly be a Darkener, or part Darkener, if that's even possible.

Sans has a habit of popping up and breaking the fourth wall whenever something is about to happen. He pops up and breaks the fourth wall at the end of the chapter.

Something about A Town Called Hometown feels off. Like it's not what you think....

Chara is one of the few characters that can override the player's decisions. No matter what, at the end of a Genocide Route, the world ends, and that save file flag is created. There are only a few characters who can do that. Asgore, who destroyed the mercy button. Asriel/Flowey, with their manipulation of the save file, and Sans. Two out of those three characters are connected to Chara, with Sans being connected to Gaster. So is it out of the question that Chara could create a world, as well as destroy it?

The only character that has an attitude event remotely similar to Jevil is Undyne.

Rouxls enjoys puzzles, similar to a character we all know and love. Papyrus. But his face looks like Gaster. And Rouxls isn't exactly as loveable. Lancer reminds me more of Papyrus.

Many of these tie into my theory, that Deltarune is a world created post-genocide route by Chara and Gaster.