Asriel

In Chapter 1, Toriel has stated that Asriel will come from college next week. Not on weekend, not exactly 7 days, but just next week.

In the LTS Update of the Demo, Sans will say a brand new phrase in Chapter 2.

Now, in Chapter 3, the Egg Man has openly implied that Chapter 1 takes place in Thursday, Ch2 in Friday, Ch3&4 in Saturday, and Ch5 in Sunday.

And what do we remember from Toby himself? On April 27, Sunday, he promised a newsletter next week. But due to calendar controversy in various regions, it took TWO WEEKS.

Does it mean that Asriel will come on Sunday, the beginning of "next week?!"

Morefore, in Chapter 4, the Old Man tells the details of LotH's Chapter 5: "vast garden charred in an inferno of jealousy". It implies that next Dark World will be at Asgore's House, who is jealous of Sans!!! And if you haven't spoke to Sans in Ch1, he will tell you this!

Considering that Chapter 5 would be the finale of "main" storyline, while Ch6&7 would be the "secret" chapters, does it mean that Papyrus will come along with Sans to Asgore?

OR

I know there's been clues that Dess may be the Knight, BUT

There's also a festival coming in Chapter 5. What if there will be another Dark Fountain on... What if the Knight is an Amalgamate?...

Alright, that's enough.

You get the idea.

And finally, let's discuss Mettaton

Before the release of Ch3+4, I thought that this clearly meant Ch3+4. But since I'm not an English person, it took me a while to understand it means "third quarter of the game".

If this game is UNDERTALE, this means a lot. But if you assume this game is actually DELTARUNE, which is split in 7 chapters, then we should calculate.

7/4*3=5,25

As I mentioned before, there's a festival coming in Chapter 5. In Ch4 you can give Tenna to Mettaton, and he will get huge inspiration from it.

Does it mean that Mettaton will finally get out of his house and come to festival as Mettatenna?

But hey, that's just a theory. A GAME THEORY.