>>532143625
The Prophecy IS the ending, that's what it represents in a meta-narrative sense. In a broader sense however, this is also about death.
Deltarune has a central theme of futility, Darkners are futile in their attempts to influence the light-world, they exist in futility until they enter the dark world. For example: When Spamton "Ran Off" from Tenna, neither of them chose that. They didn't even exist yet. That's just how the darkness interperetted what the lightners did with these objects. Even without any FRIEND Shenanigans, the laptop would have always been returned to the library, Spamton and Tenna could never have a relationship. From a meta sense, this is about how fiction cannot affect reality directly; it can only inspire real people to do things. Undertale wasn't about morality and self-defense, it was asking the player to consider fiction more deeply, to immerse themselves in it, and do fiction a favor by taking it seriously and to heart; because fiction can't do anything on its own. Deltarune's the same, the Dark Worlds, works of fiction can't do anything, unless Lightners do these works of fiction a favor and consider them beyond pure utilitarian time-wasting entertainment; consider them as messages worth listening to. Because any attempts by the Fiction itself to change reality will be futile.
Death, is also something we are futile in the face of. There is only one ending to life, death, but Toby's not a pessimist. The ending of life is not what's important. How we live life is important, we will all die one day, all our stories will end, but the important part is doing what's right, the best thing for everyone, because even if we can't change the ending, we can still make things better while we're here.