MonstrumLocationManagerFix

Monstrum mods are fine by itself but it can have problems with other mods that adds locations.
There is sometimes duplication with location proxies so you may devote double offerings to summon a boss.
And there was problem with valheimcuisine's location too. And this mod fixes that. Also patches into EWD to fix Monsterlabz locations.

MonstrumLocationManagerFix is a small BepInEx plugin for Valheim that fixes Therzie's Monstrum and MonstrumDeepNorth location registration at runtime and adds a narrow compatibility guard for Expand World Data.

What it fixes

In Therzie's location registration flow, LocationManager.Location.AddLocationToZoneSystem can use:

• UnityEngine.Object.Destroy(...)

when removing the existing enabled LocationProxy from ZoneSystem.m_locationProxyPrefab.

In this path, deferred destruction can leave the old proxy alive until later in the frame while a replacement proxy is added immediately. That can cause duplicate or conflicting location proxy behavior.

This plugin changes that call to:

• UnityEngine.Object.DestroyImmediate(...)

so the cleanup happens immediately during location setup.

It also patches ExpandWorldData.DataManager.CleanGhostInit(ZNetView) to safely skip the cleanup when a spawned ghost object has no ZDO, avoiding the server-side NullReferenceException seen during some custom location spawns.

Target mods

This plugin patches loaded assemblies that belong to these plugin GUIDs:

• Therzie.Monstrum
• Therzie.MonstrumDeepNorth
• expand_world_data

It targets these methods:

• LocationManager.Location.AddLocationToZoneSystem
• ExpandWorldData.DataManager.CleanGhostInit(ZNetView)

How it works

This is a normal BepInEx plugin, not a preloader patcher.

At startup it:

1. Detects whether Monstrum and/or MonstrumDeepNorth are loaded.
2. Finds LocationManager.Location.AddLocationToZoneSystem in those assemblies.
3. Applies a Harmony transpiler.
4. Replaces Destroy(Object) with DestroyImmediate(Object) in memory.
5. If Expand World Data is present, applies a prefix patch to CleanGhostInit(ZNetView) that bails out when the spawned ghost object has no ZDO.

Important behavior

• Install location: BepInEx/plugins
• Does not modify Monstrum.dll
• Does not modify MonstrumDeepNorth.dll
• Does not modify ExpandWorldData.dll
• Does not write marker files
• Does not clear the BepInEx cache
• Does not require anti-cheat whitelisting for modified Monstrum DLLs

Example log lines

Successful runtime patch:

• Loading [MonstrumLocationManagerFix 1.0.1]
• Patched Monstrum.LocationManager.Location.AddLocationToZoneSystem and replaced 1 Destroy call(s).
• Patched MonstrumDeepNorth.LocationManager.Location.AddLocationToZoneSystem and replaced 1 Destroy call(s).

Already fixed in the loaded target assembly:

• Verified Monstrum.LocationManager.Location.AddLocationToZoneSystem is already using DestroyImmediate.

Patch summary:

• Applied runtime patch to 2 LocationManager method(s).

Expand World Data compatibility patch:

• Applied Expand World Data compatibility patch to DataManager.CleanGhostInit(ZNetView).
• Skipped Expand World Data ghost cleanup because the spawned ZNetView had no ZDO.

Scope and safety

This plugin is intentionally narrow.

• No config file
• No gameplay changes outside the targeted location proxy cleanup
• No patching of unrelated mods beyond the narrow Expand World Data ghost cleanup guard
• No permanent modification of other mods' files

Why this exists

An earlier version solved the issue by rewriting other mods' DLL files on disk. This version keeps the same fix but applies it at runtime instead.