Deltarune is an episodic role-playing video game in development by Toby Fox as a follow-up to his 2015 video game Undertale. In the game, the player controls a human teenager, Kris, who is destined to save the world together with Susie, a monster, and Ralsei, a prince from the Dark World. During their quest to seal the Dark Fountains prophesied to end the world, the group makes both friends and foes. The combat system is turn-based and uses bullet hell mechanics. Similarly to Undertale, enemy encounters can be resolved peacefully or through violence.