Kris falls into the Underground. Play all of UNDERTALE as Kris in his Light World look, with DELTARUNE's battle system and Rude Buster as the battle theme.
What you get
Kris instead of Frisk, everywhere: walking, the umbrella in Waterfall, falling, lying down and cutscene hugs, and "Kris" wherever the story said Frisk (English and Japanese).
New lines for Kris across the story: Flowey, Toriel, Napstablook, Sans, Papyrus, Monster Kid, Undyne, Alphys, Mettaton and Asgore all react to him.
Deltarune battles in every fight, bosses included: the party panel with Kris's HP, the TP bar, Deltarune's background, enemies on the right at Deltarune's size, and the bullet box in the middle of the screen with your SOUL starting at its centre.
Six commands: FIGHT (Deltarune's timing bar, Kris swings his knife), ACT, MAGIC (X-Slash, 25% TP), ITEM, SPARE and DEFEND (+16% TP, less damage).
Grazing: bullets that pass close to your SOUL build TP and shorten the enemy's turn.
Every Undertale fight intact: each enemy keeps its own attacks, bullet patterns and ACTs.
Requirements
UNDERTALE (Steam, PC version 1.08) and DELTARUNE. KRISTALE reads both from your PC; nothing from either game is in the download.
Single player.
Good to know
The first Play builds KRISTALE's own copy of Undertale (under a minute). Your installs are untouched, and KRISTALE keeps its own saves, so you start a new game.
Photoshop Flowey's fight keeps Undertale's own look, and in Muffet's fight the box stays where Undertale puts it (her web effects are drawn around it).
Credits
UNDERTALE and DELTARUNE by Toby Fox. This is an unofficial, free fan mod. Patching by UndertaleModTool (GPL-3.0), bundled unmodified. Built with AI assistance (Claude).