How Undertale and Deltarune are connected?

[Dvayne Reaze]

Chapter 2 gave no answer. Also there is none of Deltarune forums on steam

[PlebNC (UK)]

The official statement by Toby Fox (both game's creator) and on official Deltarune website is that Deltarune isn't a sequel or prequel to Undertale and is a seperate alternative universe. Everything you did in Undertale is canon and has no influence on the events of Deltarune.

So in other words, think of it like a parallel universe. Some stuff is the same, other stuff different.

[solar]

cuz toby

[Spookypizza]

Deltarune isnt connected in undertale in any way

HOWEVER, in the early game the player can meet sans and talk with him.
One of the sentences is "hey old friend" which, is really werid,

[Blinkz]

It is most definitely connected lol

We just don't know yet. I imagine it will come together at the end of the game. Though I think it also won't affect Undertale in any major way.

[moninho]

More than once Undertale makes it clear that there are multiple universes, and Toby seems to be picking that up to write an entirely (not quite so) new one for Deltarune. A concurrent reality. The presence of Undertale characters such as Alphys and Sans seems to be incidental - they are part of multiple alternate universes of that world, and not aware of that*. So the events of Deltarune and Undertale shouldn't be very connected and shouldn't influence each other except for the ressemblances left by common characters and dialogue lines. A smart choice if you have made a massively successful game with multiple possible endings and have to depart from there to a new but relatable project :P

Except for Sans, maybe... we never know if he is joking about not knowing you or just acting surprised when we ask about his brother... we don't know enough, yet :P