FIW Bosses

A data-driven custom boss framework for NeoForge 1.21.1 and Fabric 1.20.1 — inspired by MythicMobs, built from scratch.

Define fully custom multi-phase bosses entirely through JSON files. No coding, no server restarts drop a config, run the reload command, and your boss is live.

Why FIW Bosses?

Neither Fabric nor NeoForge have a good lightweight boss framework. MythicMobs is Bukkit/Spigot only. FIW Bosses fills that gap server-side only, zero client installation required, fully JSON-driven so anyone can create bosses without touching code.

Supported Loaders

Loader Minecraft Status NeoForge 1.21.1 Active — primary development target Fabric 1.20.1 Legacy — may still receive occasional updates, but not guaranteed

Both loaders share the same JSON schema, same 42 abilities, same feature set. A boss config written for one works on the other. The only difference is the command root: /fiwboss on NeoForge, /boss on Fabric.

Features

• JSON-driven bosses — create any boss without writing a single line of code
• Multi-phase system — HP thresholds trigger phase transitions with new abilities, speeds, equipment, sounds, and particle effects
• 42 configurable abilities — melee, ranged, mobility, AoE, crowd-control, utility, and ultimates
• Pre-fight activation — boss starts passive/immortal; right-click to trigger dialogue and start the fight
• Pre-death dialogue — boss held at 1 HP on lethal hit, speaks final words, then dies
• Custom skins — use any player's skin or load a local PNG file
• Custom equipment — full item + NBT support per slot, swappable per phase
• Minion spawning — spawn any mob as a minion with caps and radius control
• Dynamic aggro — aggro switching, revenge targeting, multiplayer-friendly
• Strafing AI — bosses circle and strafe at close range
• Custom loot tables — per-item drop chances with full NBT support
• Hot reload — reload all configs without restarting the server
• Phase persistence — boss phase survives server restarts via NBT
• Server-side only — clients don't need to install anything

Quick Start

1. Drop the correct JAR into your mods/ folder (NeoForge or Fabric variant)
2. Start the server — boss folder generates at config/fiw_bosses/bosses/
3. Copy an example boss from config/fiw_bosses/examples/ into config/fiw_bosses/bosses/
4. Run the reload command (/fiwboss reload or /boss reload)
5. Spawn it with /boss spawn <id> (same for NeoForge or Fabric)

Commands

/boss spawn <id> — spawn at your location /boss spawn <id> <x> <y> <z> — spawn at coordinates /boss list — list all loaded boss IDs /boss kill <boss> — kill a specific boss /boss kill all — kill all bosses /boss reload — reload all configs (permission level 3)

Requirements

NeoForge 1.21.1 (active)

Minecraft 1.21.1 NeoForge 21.1.x Java 21 Server-side only Yes

Fabric 1.20.1 (legacy)

Minecraft 1.20.1 Fabric Loader 0.18.3+ Fabric API 0.92.2+1.20.1 Java 21 Server-side only Yes

Documentation

Full configuration reference with all fields, ability parameters, and examples available on the GitHub repository.

License

GNU General Public License v3.0

Made by Fi3w0 — built for a private SMP, shared with everyone. Developed with assistance from Claude Opus 4.6.