Deltarune

Deltarune is a Western RPG created by Toby Fox, whose demo/first chapter was released without announcement on October 31, 2018. It's a Spin-Off/Sequel/Prequel/Alternate Universe/What Have You to Undertale, albeit Fox announced it as a game for those who had completed Undertale first.

You play as Kris, the (apparently) only human resident of Hometown, a sunny suburban town populated by monsters. While searching some school material along with Suzie, the resident bully of the school, you both fall within a mystrious closet to what can only be defned as a "dark world". There, you meet the Prince of Darkness, Ralsei, who claims that the three of them together are Lightners, beings destined to travel to stop the flow of darkness into the underworld.

The game is a role-playing game like Undertale. Combat is performed similar to most standard turn-based role-playing games, choosing from a set of actions such as "Attack" or "Mercy". While the goal of the game is implicitly to avoid fights and spare monsters, this is made difficult in that Susie, who is not initially controlled by the player, tends to prefer to attack rather than have mercy, so special actions mus be made to keep her cool.

Due to its nature as an spinoff of Undertale, many spoilers for that game will go unmarked.