Mob Civil War

Minecraft 26.3 support is now available: download 1.2.1+mc26.3 for Fabric. Use the JAR and Fabric API that match your Minecraft version.

A lightweight Fabric mod for Minecraft 1.21.x and 26.x that introduces natural hostilities between Undead, Illager, and Athropod factions, creating dynamic battlefield encounters throughout your world.

Core Functionality

Civil War Mod forces natural aggression between three major hostile factions in Minecraft:

• Undead Faction: Zombies and Skeletons
• Illager Faction: Pillagers, Vindicators, Evokers, and other Illagers
• Arthropod Faction: Spiders and Cave Spiders

Behavior Details

• Natural Aggression: Mobs from opposing factions will attack each other on sight without needing to be hit first
• High Priority Targeting: Enemy factions are treated with equal priority to Players (Priority 2), meaning mobs will actively seek out and engage enemy faction members
• Proximity-Based Combat: Mobs will attack whichever valid target (Player or Enemy Faction) is closest, creating dynamic three-way battles
• Faction Coverage:
  • Undead (Zombies, Skeletons) target Illagers and Spiders
  • Illagers (Pillagers, Vindicators, Evokers, etc.) target Undead and Spiders
  • Spiders (Spiders, Cave Spiders) target Undead and Illagers

Gameplay Impact

This mod transforms the Minecraft world into a more dynamic battlefield where:

• You might stumble upon epic battles between Zombies, Pillagers, and Spiders
• Villages become more dangerous as Illagers fight off Zombie hordes while Spiders join the fray
• Strategic opportunities arise as factions weaken each other in three-way conflicts
• The world feels more alive with ongoing conflicts between hostile mobs

Technical Details

• Minecraft Version: 1.21-1.21.1, 1.21.4-1.21.11, 26.1 / 26.1.2 / 26.2 / 26.3
• Mod Loader: Fabric
• Java Version: 21+ (26.x: Java 25)
• Architecture: Mixin-based injection into entity AI goal systems
• Performance: Lightweight with minimal overhead

Compatibility

This mod only adds faction-based targeting goals to hostile mobs' AI during initialization and should be compatible with most mods. It uses standard mixin injection points and doesn't modify or remove existing game behavior, making it safe to use alongside content mods, performance mods, and most other Fabric mods.

Potential conflicts may occur with mods that completely replace mob AI systems or heavily modify entity targeting behavior, though such mods are uncommon in the Fabric ecosystem.

Stranded Soldiers (optional)

Stranded Soldiers is an optional companion; neither mod requires the other.

When both are installed on the same Minecraft version (matching +mc<version> JARs), portal defenders tagged stranded_defender receive Civil War faction targeting after Stranded Soldiers configures their spawn AI. Defenders keep player focus and no defender-on-defender infighting, and gain faction enemies (Illagers, Undead, Spiders) at priority 2; ruined portals can erupt into three-way battles.

Version support (26.x)

Minecraft 26.3 (1.2.1): now released as civil-war-1.2.1-mc26.3.jar. Requires Fabric Loader 0.19.5+, Fabric API 0.161.0+26.3, and Java 25.

Shipped (1.2.0): Minecraft 26.1, 26.1.2, and 26.2. One Fabric JAR per line (civil-war-1.2.0-mc26.*.jar), built from isolated mc26.* Gradle modules on Mojmap.

1.21.x: 1.21, 1.21.1, 1.21.4–1.21.11 (1.21.2 and 1.21.3 dropped; use a neighboring supported patch).

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