Compatibility
LethalBreed does not bolt onto vanilla zombie AI: it replaces it. The zombie is pulled out of the game's goal system and driven by LethalBreed's own engine: targeting, memory, flow field, escalation, pack. That is what makes its behavior coherent, and it is also what makes it exclusive.
One rule. Any mod that alters zombie AI or zombie behavior conflicts with LethalBreed. Two engines cannot drive the same zombie: their goals contradict each other, and what you get is the behavior of neither mod. This is not an author's preference, it is a structural constraint, and the mod actively refuses to run in that configuration.
What conflicts
Mods that add, replace or refine monster AI goals: improved hunting, door opening, horde coordination, climbing, hearing, or any rewrite of zombie behavior. A list of known mod identifiers is recorded in the mod and refused at load, but it is only a shortcut: real detection does not depend on it.
Two detection layers
| Layer | When | What it examines |
|---|---|---|
| Known list | At startup | A list of known zombie-AI mod identifiers, also declared incompatible in the manifest, and the loader then refuses to start on its own. |
| Behavioral scan | First zombie loaded | Walks the AI goals actually registered on a real zombie. Any goal belonging to neither the base game nor LethalBreed betrays a foreign injection, including from a mod the list has never heard of. |
The second layer is the one that matters: it catches any zombie-AI mod, even one never cataloged, because it observes the result rather than the name.
What happens then
| Moment | Consequence |
|---|---|
| At startup | Hard stop before the server ever runs, with a message naming the offending mod. Nothing has been written to the world yet. |
| In session | Red message broadcast to every player, then a clean server shutdown: the current tick finishes and the world saves normally. Never a crash mid-save. |
Overriding it. Setting failOnAiConflict to
false lets the mod start despite the conflict, with a warning. Zombie
behavior then becomes unpredictable and no guarantee on this wiki holds any more. It is a diagnostic
switch, not a recommended configuration.
What is perfectly safe
A mod is only a conflict if it touches behavior. Everything else coexists without the slightest friction:
- Optimisation and performance: they speed the game up without changing goal logic at all. Several are even explicitly recommended here.
- Rendering, shaders, resource packs: purely visual, including those that re-skin zombies.
- Interface, maps, profiling, server utilities: no contact with the AI.
On dependencies, LethalBreed stays deliberately self-contained: it requires only the loader's API, already stated on its distribution page. Everything else is optional, see Installation.