>>529079241
The neutral ending will be one that touches on escapism, being the original themes toby based DELTARUNE upon. However, he grew attatched to his creation to where he despaired at their fates.
This is what Gaster and the shadow crystals represent - a desire to rewrite the story for a brighter ending. The Pure Crystal will open a path to saving Dess, to letting Ralsei be with his friends, and to create the best ending possible for everyone - of the same sort as the True Pacifist ending was for UNDERTALE.