
Fiw Bosses
A data-driven custom boss framework for Forge, NeoForge and Fabric Define multi-phase bosses and minions with configurable abilities entirely through JSON no coding, no restarts.
Screenshots

About this Mod
⚔️ FIW Bosses
Build the boss fight you've always wanted — from a text file.
Phases. Minions. Loot. Dialogue. Custom skins. 50+ abilities.
No Java. No restarts. No combat-modding degree required.
The pitch
Vanilla has three bosses. You've beaten all of them.
FIW Bosses hands you the toolkit Mojang didn't: drop a JSON file into config/fiw_bosses/bosses/, run /boss reload, and a fully custom encounter is live on your world — changing tactics as its health drops, summoning minions, taunting your players, and dropping exactly the loot you decide.
It isn't one hardcoded boss bolted onto the game. It's a framework: HP-threshold phases, per-phase ability loadouts, custom minions with their own AI, pre-fight and pre-death dialogue, custom skins, hot reload — one config schema that behaves the same on every loader and version it supports.
🧩 Both-sides mod. Install the matching jar on the server and every client that joins it.

Sixty seconds to your first boss
config/fiw_bosses/bosses/storm_caller.json
{
"id": "storm_caller",
"displayName": "&b&lStorm Caller",
"health": 500,
"speed": 0.28,
"phases": [
{
"hpThresholdPercent": 1.0,
"abilities": [
{ "type": "chain_lightning", "cooldownTicks": 120, "params": { "bounces": 5, "damage": 10 } },
{ "type": "beam", "cooldownTicks": 180, "params": { "damage": 4 } }
]
}
]
}
/boss reload
/boss spawn storm_caller
That's the whole loop. Tweak the file, reload, fight again — no restart, ever.
What you can build
🔥 Phase-based fights — every boss can rewrite its own rules as it bleeds. Each phase changes speed, damage, equipment, the minion pool, transition messages, sounds, particles, and its entire ability set.
🧠 Eight movement styles — hit_and_run, guard_point, phase_walk, hover, sniper, berserk, plus classic strafing or plain vanilla pathing. Your sniper kites; your berserker hunts.
👥 Custom minions — true FIW minions with skins, gear, abilities, AI modes and loot, or plain vanilla mobs for quick summons. Minions can escort the boss, hold a position, or fight on their own.
🎭 Disguises — keep full FIW logic but render a boss or minion as any vanilla or modded mob with renderEntity, or use a real player skin. Your "zombie" can cast meteors.
💬 Fight flow & dialogue — start a boss dormant and invulnerable until a player right-clicks it; play pre-fight lines, then begin. Hold it at 1 HP for last words before it falls. Every chat message is optional — silent bosses are one omitted param away.
🛡️ Damage protection — per-boss, per-phase, and per-minion damage multipliers keyed by weapon item, damage type, or category. Tame the overpowered mace/spear ("minecraft:mace": 0.2), resist potions ("magic": 0.3), or grant true immunities ("fall": 0) — made for servers with custom weapons.
⚔️ Factions — allied bosses and minions never turn on each other and their AoE can't hurt allies, with per-entity switches (damageFactionAllies, targetFactionAllies, damageOwnGroup) when you want infighting.
🌊 Water & lava handling — no more river cheese: bosses can chase players into water (canSwim), never drown, sink and fight underwater (floats: false), swim faster, ignore currents, and shrug off lava (fireImmune).
🎲 Loot ranges — roll random drop amounts with minCount/maxCount (10–120 diamonds at 50% chance); big rolls split into stacks automatically.
♻️ Hot reload & persistence — /boss reload re-reads everything live, deleted configs are removed from the world, and a boss's phase survives server restarts.
50+ abilities, mixed and matched
Abilities are small, tunable attack modules. Stack them on a phase, set cooldowns, tune the params, and a moveset is born.
| Ability | What it does |
|---|---|
domain |
Seals players in a sphere with its own attack set |
phantom_dash |
Wall-clipping zigzag dashes that snap to safe ground |
rift_cleave |
Tears a delayed damaging line through the floor |
fear_burst |
Warden-style soul burst: Darkness, Weakness, knockback |
mirror_image |
Particle decoys, invisibility, position swaps |
wither_crown |
Orbiting wither skulls that fire one by one |
last_breath |
Low-HP channel — fail to interrupt it and eat a soul blast |
rewind |
Records position + health and snaps back when low |
second_wind |
One-shot auto-revive that negates a fatal blow |
adaptation |
Grows resistant to whatever's been hurting it most |
blink_strike |
Telegraphs a target, blinks in, and punishes nearby players |
curse_bomb |
Delayed player bombs that force the group to spread out |
soul_tether |
Chains players to the boss and punishes broken tethers |
wind_charge |
Mace-style jump-slam, no self fall damage, damage fully config-driven regardless of what's equipped |
…and dozens more — slams, beams, meteors, orbital strikes, tornadoes, sonic booms, judgment marks, divine executions, summons, heals, shields, and ultimates. The full list and every parameter live in the documentation.
Supported versions
| Loader | Minecraft | Java |
|---|---|---|
| Fabric | 1.21.11 | 21 |
| NeoForge | 1.21.11 | 21 |
| Fabric | 1.21.8 | 21 |
| NeoForge | 1.21.8 | 21 |
| Fabric | 1.21.1 | 21 |
| NeoForge | 1.21.1 | 21 |
| Fabric | 1.20.1 | 17 |
| Forge | 1.20.1 | 17 |
Fabric builds need Fabric API. One boss file behaves the same on all eight targets.
Optional: Fiw Custom Items — when present, equipment and loot can reference its items by toolId; when absent, those entries are skipped and nothing breaks.
Commands
/boss needs op level 2; /boss reload needs op level 3.
/boss spawn <id> [x y z] [count] /boss list /boss kill <id> | all
/boss minion spawn <id> [count] /boss minion list /boss minion kill <id> | all
/boss reload
📖 Documentation · 🐛 Report a bug · GPL-3.0
Made by Fi3w0 for SMP-style custom fights — shared for anyone who wants stronger bosses without building a combat mod from scratch.
Available Versions
How to Install Fiw Bosses on Your Server
Order Server
Order a Minecraft Java server with at least 3 GB RAM (4 GB recommended).
Set fabric Loader
In the panel under "Egg", select the fabric loader and matching Minecraft version (1.21.11).
Install Mod
Open the mod browser in the dashboard and search for "Fiw Bosses". Click "Install" – done! Alternatively, upload the .jar via SFTP to the /mods folder.
Compatibility
Mod Loaders
Minecraft Versions
1.21.11, 1.21.8, 1.21.1 (+1 more)
Server-side
✓ RequiredRecommended RAM
4 GB(min. 3 GB)Frequently Asked Questions
Fiw Bosses server crashes on startup – what to do?
Most common cause: wrong fabric version or insufficient RAM. Check the server log (latest.log) for "OutOfMemoryError" or "Mixin" errors. With Mado Hosting: ensure at least 3 GB RAM is allocated and the loader matches the mod version (1.21.11). You can switch loaders with one click in the panel.
Is Fiw Bosses compatible with fabric and forge and neoforge?
Fiw Bosses officially supports fabric, forge, neoforge for Minecraft 1.21.11, 1.21.8, 1.21.1. Note: Forge and Fabric mods are NOT cross-compatible – pick one loader and stick with it. The Mado dashboard automatically detects incompatible loader combinations.
Server lagging with Fiw Bosses – how to optimize performance?
Recommended RAM: 4 GB (per 8 players). Use /spark profiler to check if Fiw Bosses consumes the most tick time. Common fixes: reduce server view-distance to 8-10, install "performant" or "starlight" as supplementary mods on Forge. With Mado Hosting, your server runs on NVMe SSDs with dedicated CPU cores for minimal latency.
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