The overarching antagonist of Deltarune. It is a living shadow that appears mainly as an androgynous humanoid (notably possessing a pair of antlers and stigmata-like holes in its hands resembling W.D. Gaster's) though it is capable of shapeshifting. It makes its first appearance as the final boss fight/Shadow Crystal bearer of Chapter 3, and acts as the main antagonist of Chapter 4.
