List of Undertale and Deltarune characters

Undertale and Deltarune are fantasy role-playing video games developed by Toby Fox. They take place in different fictional universes, but feature many of the same characters. Undertale is set in a world where monsters once coexisted with humans on the planet's surface, but, after an ancient war, were trapped in the Underground and forgotten. The game follows Frisk, a human child who falls into the Underground via an opening adjacent to Mount Ebott, and seeks to escape.

In Deltarune, considered a spiritual successor to Undertale, humans and monsters still coexist. Set in Hometown, the game follows Kris, who discovers a Dark World, an alternate view of reality inhabited by Darkners, living representations of real-world objects. They embark on a quest to close the Dark Fountains giving these Worlds form before darkness overtakes the real world.

The following is a list of major characters who appear in one or both games in the series. The characters have been praised by critics and fans for their humor and in-depth characterization shown through different moral choices. Some characters gained notoriety for their ability to break the fourth wall, manipulating gameplay elements normally only accessible to the player, such as saving.