Critfall

Critfall brings tabletop D20 combat to Minecraft. Every attack rolls a d20 against the target’s Armor Class.
A hit rolls damage dices, natural 20s crit and natural 1s can fumble. Every mechanic has its own switch, and every number comes from
data you can change.

Attack rolls against Armor Class

Melee hits, arrows, thrown tridents and spells roll a d20 plus an attack bonus against the target’s Armor Class. A miss deals no damage. A hit rolls the weapon’s damage dice. The action bar shows the roll, and the health the hit actually took when armor or Resistance changed it.

Natural 20s crit

A natural 20 always hits and deals the most its dice can roll. It can also slow the target or knock it back, and a line in chat marks the moment. A jump attack rolls with advantage: two d20s, keep the higher.

Natural 1s fumble

A natural 1 always misses, and a second d20 decides whether it turns into a fumble. A fumble can land on whoever stands nearest. After a fumble, natural 1s are plain misses for 10 seconds, so fast fights don’t fumble all the time. Weapon damage on a fumble is off until you turn it on, and datapacks can add fumbles that drop the weapon, hurt the attacker or make them stumble.

Stats for every mob and weapon

Vanilla mobs and weapons come with profiles: Armor Class, attack bonus, damage dice and crit range. Mobs and weapons from other mods get stats worked out from their attributes, so a modpack works without setup. /critfall inspect shows what a mob rolls with and which profile it came from.

For pack makers and mod developers

Profiles for mobs, weapons and spells are datapack JSON, matched by id or tag. /critfall generate writes an editable profile for every mob and weapon in the pack, and /critfall report lists which ones have a profile and which use worked out stats. Dry run shows every roll while vanilla damage still applies, so you can tune a pack in normal play. Three presets set crits and fumbles: Tempered (the default), Classic and Lite.

Mods build on the public Java API in studio.modroll.critfall.api: roll events, RollService and a dice parser. Checks, Initiative and the Headless Horseman use only this API. KubeJS scripts can call it too, with examples in the repo.

Requires

• Minecraft 1.21.1
• NeoForge 21.1 or newer, or Fabric Loader 0.16.9 or newer with Fabric API
• On a server, install it on the server. On clients it is optional: without it, players still see the roll as plain text, without the flavor lines, sounds and particles.

Optional

• Mod Menu on Fabric, for the config button in the mod list.

Works with

• Critfall: Checks: ability scores feed Critfall’s attack bonus, damage, Armor Class and saving throws.
• Critfall: Initiative: fights become turn based encounters. Critfall still rolls every attack and save.
• Critfall: Headless Horseman: a Halloween boss whose attacks, damage and saves Critfall rolls.
• Spell mods that tag their damage as magic: spells roll to hit or call for a saving throw. Tested with Iron’s Spells ‘n Spellbooks and Ars Nouveau on NeoForge.

Open the config screen from the mod list: Mods → Critfall → Config on NeoForge, or the config button in Mod Menu on Fabric. The first page has a preset (Tempered, Classic or Lite) and the switches most players want. All settings has every rule. Save applies the rules at once.

The rules live in config/critfall/rules.json and are read again on /reload. On a server, the server’s file applies. Each player’s config/critfall/client.json turns the readout, flavor lines, sounds and particles on or off.

Main options

config/critfall/rules.json. Options in bold are on the first page of the config screen.

config/critfall/client.json

The full reference, with every value each option takes, is in docs/rules-config.md.

All commands need operator permission.

Free to use in any modpack.

• Critfall on modroll.studio
• Source
• Issues