> For the complete documentation index, see [llms.txt](https://axiomemu.gitbook.io/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://axiomemu.gitbook.io/docs/data/monster/monstersetbase.md).
# MonsterSetBase
Controls where and how monsters spawn across all maps. The server scans one folder of per-map XML files at startup and appends every entry into a single global spawn table.
## File Location
**Per-map spawns:** `Data/Monster/MonsterSetBase/*.xml` (one file per map)
No master registry file ships with AXIOM-EMU. The server scans the `MonsterSetBase/` directory and loads every `.xml` file it finds.
{% hint style="info" %}
**Unified folder**: Castle Siege event maps (Castle Siege, Land of Trials, Crywolf, Barracks, Refuge, Loren Market) were historically split into a separate `MonsterSetBaseCS/` folder. That split is gone; everything lives in `MonsterSetBase/`. On non-Castle-Siege deployments, NPCs on CS-only maps still spawn but their interaction handlers self-gate, so they are inert.
{% endhint %}
## Dependencies
| Depends On | Purpose |
| -------------------------------------------- | ----------------------------------------------------------------------------- |
| [Monster.xml](/docs/data/monster/monster.md) | Spawns reference monster stats by Class (Index) |
| [MapManager.xml](/docs/data/mapmanager.md) | Entries on a map not enabled by this server are silently dropped at load time |
| Used By | Purpose |
| ------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Map loading | Server reads spawn files during map initialization |
| Event systems | Blood Castle, Devil Square, Illusion Temple, Imperial Guardian, Raklion, Crywolf, Castle Siege, Chaos Castle, and Invasion Manager all scan the spawn table for their Type 3 / Type 4 entries |
## File Structure
### Per-Map Spawn Files
Each map has its own file: `MonsterSetBase/000 - Lorencia.xml`, `MonsterSetBase/001 - Dungeon.xml`, etc. The filename is documentation only; the actual map is chosen by each entry's `Map` attribute. Files load in alphabetical order and their entries are appended into one global spawn table, so adding or renaming a file is all that is needed to register new spawns.
Map numbers match the game's internal map IDs (00 = Lorencia, 01 = Dungeon, 02 = Devias, etc.) and must match the Map value written inside each entry.
## Spawn Entry Attributes
| Attribute | Type | Description |
| --------- | ------ | -------------------------------------------------------------------------- |
| `Type` | int | Spawn type (see Spawn Types below) |
| `Class` | int | Monster Index from Monster.xml |
| `Map` | int | Map number (00 = Lorencia, 01 = Dungeon, etc.) |
| `Dis` | int | Roaming distance from spawn point (in tiles) |
| `X` | int | Spawn X coordinate |
| `Y` | int | Spawn Y coordinate |
| `TX` | int | Target X coordinate (Type 1/3 only) - defines spawn area with X |
| `TY` | int | Target Y coordinate (Type 1/3 only) - defines spawn area with Y |
| `Dir` | int | Facing direction (0-7, or -1 for random) |
| `Count` | int | Number of monsters to spawn (Type 1/3 only, minimum 1 if 0) |
| `Value` | int | Event identifier (Type 3 only) - used by Invasion Manager to filter spawns |
| `Comment` | string | Description (optional, for admin reference) |
## Spawn Types
| Type | Name | Behavior | Use Case |
| ---- | ----------- | ---------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------- |
| 0 | Fixed | Single monster at exact X/Y; respawns at the same location | NPCs, guards, stationary bosses |
| 1 | Group | Count monsters spawn randomly inside the (X,Y)-(TX,TY) rectangle; each respawn re-rolls a point in the same rectangle | Normal hunting zones |
| 2 | Spot | Single monster; loader offsets X/Y by -3..+3 once at load, then every (re)spawn picks a fresh point within +/-3 of that offset X/Y | Scattered individual spawns |
| 3 | Event | Same geometry as Type 1; filtered out of normal init and activated by Invasion Manager using the Value field | Invasion Manager, White Wizard events |
| 4 | Event Fixed | Single monster at exact X/Y; filtered out of normal init and activated by event code matching on MonsterClass and Map | Blood Castle, Devil Square, Illusion Temple, Imperial Guardian, Raklion |
### Type 0: Fixed Spawn
```xml
```
* Spawns exactly 1 monster at X=122, Y=110
* Dis="00" means the monster cannot roam
* Dir is a 0-7 facing index; use -1 for random
* Use for NPCs and bosses at specific locations
### Type 1: Group Spawn
```xml
```
* Spawns 7 spiders at (187,121) because TX=X and TY=Y (the spawn rectangle collapses to a single tile)
* TX/TY must be set larger than X/Y to create a real spawn area; otherwise every unit of `Count` spawns at the exact point
* `Dis="10"` allows each monster to roam 10 tiles from its spawn point
* `Dir="-1"` means random facing
* Use for normal monster packs in hunting zones
### Type 2: Spot Spawn
```xml
```
* Spawns 1 monster within a 7x7 box centered on the configured X/Y (coordinates offset by -3..+3 on each axis)
* The loader offsets the stored X/Y once at load time, then picks a fresh random point within +/-3 of that offset X/Y on every spawn and respawn
* Good for scattered individual monsters that should not cluster
* Commonly used in Noria for BeetleMonster and ForestMonster
### Type 3: Event Spawn (Invasion Manager)
```xml
```
* Similar to Type 1 but controlled by Invasion Manager and event systems
* Count monsters spawn randomly between (X,Y) and (TX,TY)
* **Value attribute** is used by event systems to filter/identify spawn groups
* Used by White Wizard invasions and custom event systems
* NOT directly used by Blood Castle, Devil Square (they use Type 4)
### Type 4: Event Fixed Spawn
```xml
```
* Single monster at exact X/Y for event systems
* Behaves like Type 0 but filtered by event code (Type 3/4 are excluded from normal spawns)
* Used by Blood Castle, Devil Square, Illusion Temple, Imperial Guardian, Raklion
* Event systems programmatically control when these spawns are activated
## Direction Values
| Dir | Meaning |
| --- | ------------------------------------------------------------- |
| 0-7 | Facing index (MU Online standard 8-way facing) |
| -1 | Random; loader rolls a fresh 0-7 value per entry at load time |
TODO: verify exact compass mapping of each 0-7 value against the client's direction table.
## Important Behavior
### Spawn Timing
{% hint style="info" %}
**Initial spawn**: All Type 0, 1, and 2 monsters spawn when the GameServer starts and loads maps. Type 3 and 4 entries are skipped during the normal spawn pass and are instantiated later by event systems on their own schedules.
**Respawn**: After death, monsters respawn based on their `RegenTime` in Monster.xml. The respawn location depends on spawn type:
* Type 0 / Type 4: exact same X/Y
* Type 1 / Type 3: fresh random point inside the (X,Y)-(TX,TY) rectangle
* Type 2: fresh random point inside +/-3 of the load-time offset X/Y (re-rolled every respawn)
{% endhint %}
### Coordinate System
* Coordinates are in tiles (not pixels)
* Origin (0,0) is typically top-left corner
* Maximum coordinates vary by map (usually 255x255 or similar)
* Invalid coordinates = monster spawns but is unreachable/invisible
### Dis (Roaming Distance)
* Dis="00" = Monster cannot move (stays at spawn point)
* Dis="10" = Monster can wander up to 10 tiles from spawn point before AI forces return
* Distance is calculated as Euclidean distance from spawn point (sqrt formula)
* Too high Dis on maps with walls = monsters may appear to walk through walls when returning
* NPCs should always have Dis="00" to prevent walking away
{% hint style="warning" %}
The roaming distance check uses the monster's current spawn point, not the original config X/Y. For Type 2, the spawn point is the randomized location rolled at spawn time, so the roam box travels with each respawn.
{% endhint %}
### Count Behavior
Type 1 and 3 spawn exactly `Count` monsters:
* `Count="007"` spawns 7 monsters
* `Count="000"` spawns 1 monster (the loader converts zero to one)
* Each monster rolls its initial location inside the (X,Y)-(TX,TY) rectangle
* On death, the respawn rolls a new location in the same rectangle (Type 1/3 only)
Internally the loader expands each Type 1 / Type 3 entry into `Count` individual spawn slots in the 20000-slot global table. A `Count="050"` entry consumes 50 slots.
### TX/TY as Spawn Area
For Type 1/3, (X,Y) and (TX,TY) define a rectangular spawn area:
* If `TX=X` and `TY=Y`, every unit of `Count` spawns at the exact point (the box collapses to a single tile). Use this only when you want stacked spawns
* If `TX` > `X` or `TY` > `Y`, spawns are spread across the rectangle (must be greater than, not just not equal)
* Example: `X="100" Y="100" TX="120" TY="120"` = 20x20 tile spawn zone
* The picker retries up to 100 times to find a walkable tile before giving up on that roll
### Event Spawn Filtering (Type 3/4)
{% hint style="info" %}
Type 3 and 4 spawns are **NOT included** in the normal monster spawn during map initialization. They are filtered out and only activated by event systems:
* **Type 3**: Invasion Manager uses the `Value` attribute to match spawn groups
* **Type 4**: Blood Castle, Devil Square, Illusion Temple, Imperial Guardian, and Raklion use `MonsterClass` and `Map` to find specific spawns
This allows event monsters to be defined alongside normal monsters without interfering with regular gameplay.
{% endhint %}
## Examples
{% tabs %}
{% tab title="NPC (Fixed)" %}
```xml
```
Spawns Trainer NPC at fixed location in Lorencia, cannot roam (Dis=0), facing index 3.
{% endtab %}
{% tab title="Monster Group" %}
```xml
```
Spawns 7 Bull Fighters at (201,69) with 10-tile roaming range, random facing. Because TX=X and TY=Y, all 7 start on the same tile before they roam apart.
{% endtab %}
{% tab title="Scattered Spawns" %}
```xml
```
Spawns 50 Spiders across an 80x100 tile zone (from 140,80 to 220,180), creating a dense hunting area.
{% endtab %}
{% tab title="Boss Spawn" %}
```xml
```
Spawns Gorgon boss at (125,125), can roam 5 tiles, facing index 0. Respawn time is controlled by Monster.xml RegenTime.
{% endtab %}
{% tab title="Event Spawn (Blood Castle)" %}
```xml
```
Defines a gate spawn for the Blood Castle event. Type 4 is filtered out of the normal map initialization spawn pass; Blood Castle finds it by scanning the spawn table for matching MonsterClass and Map.
{% endtab %}
{% tab title="Scattered Individual Monsters" %}
```xml
```
The loader offsets each entry's X/Y by -3..+3 once at load time. On every spawn and respawn the server rolls a fresh random point inside +/-3 of that offset X/Y, so each entry occupies a 7x7 tile box.
{% endtab %}
{% endtabs %}
## Per-Map Spawn Files
Each map has its own spawn file. The folder ships with files covering at least the following map IDs:
| Map ID | File | Map Name |
| --------- | ------------------------------------------------------------------------------------- | --------------------------- |
| 00 | `000 - Lorencia.xml` | Lorencia |
| 01 | `001 - Dungeon.xml` | Dungeon |
| 02 | `002 - Devias.xml` | Devias |
| 03 | `003 - Noria.xml` | Noria |
| 04 | `004 - Lost Tower.xml` | Lost Tower |
| 06 | `006 - Arena.xml` | Arena |
| 07 | `007 - Atlans.xml` | Atlans |
| 08 | `008 - Tarkan.xml` | Tarkan |
| 09 | `009 - Devil Square 1.xml` | Devil Square (lower tiers) |
| 10 | `010 - Icarus.xml` | Icarus |
| 11-17, 52 | `011 - Blood Castle 1.xml` ... `017 - Blood Castle 7.xml`, `052 - Blood Castle 8.xml` | Blood Castle |
| 18-23, 53 | `018 - Chaos Castle 1.xml` ... `023 - Chaos Castle 6.xml`, `053 - Chaos Castle 7.xml` | Chaos Castle |
| 24-29, 36 | `024 - Kalima 1.xml` ... `029 - Kalima 6.xml`, `036 - Kalima 7.xml` | Kalima |
| 30 | `030 - Castle Siege.xml` | Castle Siege |
| 31 | `031 - Land of Trials.xml` | Land of Trials |
| 32 | `032 - Devil Square 2.xml` | Devil Square (higher tiers) |
| 33 | `033 - Aida.xml` | Aida |
| 34 | `034 - Crywolf.xml` | Crywolf |
| 37-39 | `037 - Kanturu 1.xml` ... `039 - Kanturu 3.xml` | Kanturu |
| 40 | `040 - Silent.xml` | Silent Map |
| 41 | `041 - Barracks.xml` | Barracks of the Balgass |
| 42 | `042 - Refuge.xml` | Refuge of the Balgass |
| 45-50 | `045 - Illusion Temple 1.xml` ... `050 - Illusion Temple 6.xml` | Illusion Temple |
| 51 | `051 - Elbeland.xml` | Elbeland |
Kanturu 3 (map 39) also has dedicated spawn entries in [`KanturuMonsterSetBase.xml`](/docs/data/monster/kanturumonstersetbase.md) loaded separately for the Kanturu event.
{% hint style="info" %}
When adding spawns to a map, edit the corresponding map file (e.g., `000 - Lorencia.xml` for Lorencia spawns); there is no parent MonsterSetBase.xml file.
{% endhint %}
## Common Tasks
### Add Monster Spawn to Map
1. Find the map file (e.g., `002 - Devias.xml`)
2. Add a new `` entry
3. Set Type (usually 1 for monster groups)
4. Set Class to monster Index from Monster.xml
5. Set X/Y coordinates and Count
### Increase Monster Density
Find existing spawn entries and increase `Count`:
```xml
```
### Create Dense Hunting Zone
Add multiple spawn entries with overlapping areas:
```xml
```
Creates 45 Hell Hounds across overlapping zones for intense hunting.
### Remove Monster from Map
Delete or comment out the spawn entry:
```xml
```
### Move Boss Location
Change X and Y coordinates:
```xml
```
## Common Issues
{% hint style="warning" %}
**Monsters spawn inside walls.** Check that X/Y coordinates are on walkable terrain. Use in-game /move command to verify coordinates are valid.
{% endhint %}
{% hint style="warning" %}
**Count="000" spawns 1 monster, not 0** (only for Type 1/3). The code automatically converts Count=0 to Count=1. To disable a spawn, delete the entry or comment it out with ``.
{% endhint %}
{% hint style="warning" %}
**Changes don't appear immediately.** Monsters already spawned remain until they die. For immediate updates, restart the GameServer or use /reload commands if available.
{% endhint %}
{% hint style="info" %}
**Dis too high causes wall clipping.** If monsters appear to walk through walls, reduce their Dis value to keep them within the intended area. The pathfinding return-to-spawn logic can cause monsters to walk through obstacles.
{% endhint %}
{% hint style="warning" %}
**Type 2 spawns are not deterministic.** The loader rolls a -3..+3 offset on each restart, then every individual spawn and respawn rolls a fresh point inside +/-3 of that offset. Do not use Type 2 when you need a precise fixed location.
{% endhint %}
{% hint style="danger" %}
**Hard ceiling of 20000 spawn entries across all maps.** Each entry past the limit is silently dropped. For Type 1 and Type 3 the loader creates one spawn slot per unit of `Count`, so `Type="1" Count="050"` consumes 50 slots. On boot the GameServer logs `[MonsterSetBase] loaded N / 20000 entries`; if the cap is hit it also logs `[MonsterSetBase] CAP HIT - trailing spawn entries silently dropped. Raise MAX_MSB_MONSTER in MonsterSetBase.h`. Vanilla S6 spawn data expands to \~10035 entries on its own; the previous 10000-slot limit silently dropped the tail of Arkania and any later map.
{% endhint %}
{% hint style="warning" %}
**Entries on disabled maps are dropped.** If the `Map` value belongs to a map this GameServer instance does not run (per [MapManager.xml](/docs/data/mapmanager.md)), the loader silently skips the entry instead of logging an error.
{% endhint %}
{% hint style="info" %}
**Per-map loading**: The server scans the `MonsterSetBase/` folder and loads every `.xml` file inside it into one global spawn table. There is no master registry file.
{% endhint %}
## Related Pages
* [Monster.xml](/docs/data/monster/monster.md) - Stats, RegenTime, and level for every Class referenced here
* [KanturuMonsterSetBase.xml](/docs/data/monster/kanturumonstersetbase.md) - Separate Kanturu-event spawn list for map 39
* [MapManager.xml](/docs/data/mapmanager.md) - Map index table controlling which maps this server actually runs