Icarus Mount Editor

A Python toolkit for editing mount save data in Icarus.

Features:

• Transform mount types (Horse to Tusker, etc.)
• Clone mounts with unique IDs
• Reset talent points

Why I Made This My woolly mammoth refused to fight in the desert. Just stood there, overheated and passive, while enemies swarmed our base. In-game solutions failed, and I couldn't install mods on my friends' server. So I asked Claude to help me hack the save files instead. One day later: a working toolkit and a new Ubi mount that fights in the desert.

Note: Renaming mounts can be done in-game, so this tool focuses on operations the game doesn't support.

Requirements

• Windows (Icarus is a Windows game; Linux users with Proton can use --file flag)
• Python 3.8+
• No external dependencies

Installation

# Clone or download this folder
cd icarus-mount-editor

# No external dependencies required - uses Python 3.8+ standard library only

Quick Start (CLI)

The easiest way to use the editor is via the command-line interface:

# List all your mounts
python mount_cli.py list

# Show detailed info for a mount
python mount_cli.py info 0

# Clone a mount
python mount_cli.py clone 0 "Shadow II"

# Set mount to max level
python mount_cli.py level 0 50

# Transform mount type
python mount_cli.py type 0 Tusker

# Change horse color (A1=brown, A2=black, A3=white)
python mount_cli.py variant 0 A3

# See all available commands
python mount_cli.py --help

The CLI auto-detects your Steam ID if you only have one Icarus account.

CLI Commands

Information

Command	Description
list	List all mounts with type and level
info <mount>	Show detailed mount properties
types	List available mount types
validate	Check mount data integrity

Modification

Command	Description
rename <mount> <name>	Rename a mount
level <mount> <level>	Set mount level (1-50)
type <mount> <type>	Change mount type
clone <mount> <name>	Clone a mount
delete <mount>	Delete a mount
variant <mount> <A1|A2|A3>	Change horse color variant
skin <mount> <index>	Set cosmetic skin index
reset-talents <mount>	Reset talents (refund points)

Utility

Command	Description
backup	Create a manual backup
restore	List or restore from backup
config	Show configuration

Quick Start (Python API)

For scripting or advanced usage:

from mount_editor import MountEditor

# Load your mounts (find your Steam ID in your profile URL)
editor = MountEditor(steam_id='YOUR_STEAM_ID')
editor.load()

# List all mounts
for mount in editor.list_mounts():
    print(f"[{mount.index}] {mount.name} ({mount.mount_type})")

# Transform to a different type (optionally with a new name)
editor.change_mount_type(0, "Tusker", new_name="Oliphaunt")

# Clone a mount as a different type
editor.clone_mount(0, "Shadowfax Jr", new_type="WoollyMammoth")

# Save changes (creates backup automatically)
editor.save(backup=True)

Available Mount Types

Rideable Mounts (10 types)

Type	Key	Description
Terrenus	Terrenus	Wild alien creature. Fast, balanced. Tamed from the wild.
Horse	Horse	Actual Earth horse from Workshop. 3 color variants (A1/A2/A3).
Moa	Moa	Fastest mount. Small inventory, two slots.
Arctic Moa	ArcticMoa	Cold-resistant arctic variant of Moa.
Buffalo	Buffalo	Strong, slow mount. Large carrying capacity.
Tusker	Tusker	Slowest but strongest. Found in arctic Styx regions.
Zebra	Zebra	Fast mount similar to Terrenus.
Wooly Zebra	WoolyZebra	Cold-resistant woolly variant of Zebra.
Ubi	SwampBird	Swamp-dwelling bird mount.
Woolly Mammoth	WoollyMammoth	Massive arctic mount with huge carrying capacity.

Workshop Horse Variants

Workshop horses are unlocked via talents and come in 3 color variants (all with identical stats):

• Workshop_Creature_Horse_A1 - Brown horse
• Workshop_Creature_Horse_A2 - Black horse
• Workshop_Creature_Horse_A3 - White horse

The color is determined by the AISetupRowName property (e.g., Mount_Horse_Standard_A3). Stats: HP 1440, Stamina 373, Speed 805, Sprint 1518, Carry 220kg.

Companion-Only (Cannot be mounted)

Type	Key	Notes
Blueback Daisy	BluebackDaisy	Has skill tree. Summons as follower only.
Mini Hippo	MiniHippo	No skill tree. Quest reward creature.

Unreleased Mounts

Type	Status
BP_Mount_Raptor_C	Blueprint doesn't exist yet
BP_Mount_Slinker_C	Blueprint doesn't exist yet

API Reference

MountEditor

class MountEditor:
    def __init__(self, steam_id: Optional[str] = None)
    def load(self) -> None
    def save(self, backup: bool = True) -> Path
    def list_mounts(self) -> List[MountInfo]
    def get_mount(self, index: int) -> MountData
    def change_mount_type(self, index: int, new_type: str, new_name: str = None) -> None
    def clone_mount(self, source_index: int, new_name: str, new_type: str = None) -> int
    def delete_mount(self, index: int) -> None
    def set_mount_level(self, index: int, level: int) -> None
    def reset_mount_talents(self, index: int) -> int  # Returns count reset
    def set_horse_variant(self, index: int, variant: str) -> None  # A1/A2/A3
    def set_cosmetic_skin(self, index: int, skin_index: int) -> None
    def validate_mount(self, index: int) -> List[str]

Working with Properties

from mount_editor import MountEditor, find_property

editor = MountEditor(steam_id='YOUR_STEAM_ID')
editor.load()

mount = editor.get_mount(0)

# Access specific properties
experience = find_property(mount.properties, 'Experience')

# Reset talents using the editor method
reset_count = editor.reset_mount_talents(0)
print(f"Reset {reset_count} talents")

# Set horse variant (Workshop horses only)
editor.set_horse_variant(0, 'A3')  # A1=Brown, A2=Black, A3=White

editor.save()

File Locations

Icarus Save Data Structure

All Icarus save data is stored in:

%LocalAppData%\Icarus\Saved\

On Windows, this expands to:

C:\Users\{Username}\AppData\Local\Icarus\Saved\

Player Data (Per-Account)

PlayerData\{SteamID}\
├── Mounts.json          # Global mount storage (this tool edits this)
├── Characters\          # Character profiles
├── Prospects\           # Per-session world saves
│   ├── {ProspectName}.json
│   └── ...
└── MetaInventory\       # Workshop/outpost items

Finding your Steam ID:

• Visit steamid.io and enter your profile URL
• Or check the folder names in PlayerData\ - there's usually only one

Mount Data Format

Mounts.json structure:

{
  "SavedMounts": [
    {
      "DatabaseGUID": "unique-guid",
      "MountName": "Horse",
      "MountLevel": 25,
      "MountType": "Horse",
      "MountIconName": "12345",
      "RecorderBlob": {
        "BinaryData": [/* base64-decoded byte array */]
      }
    }
  ]
}

The RecorderBlob.BinaryData contains UE4 serialized properties including:

• MountName, AISetupRowName, ActorClassName
• Experience, Talents, CharacterRecord
• ObjectFName, ActorPathName, IcarusActorGUID
• CosmeticSkinIndex (appearance variant)
• bIsWildTame (wild vs bred flag)

For complete property documentation, see SCHEMA.md.

Game Installation (PAK Files)

Mount blueprints are defined in the game's PAK files:

{Steam Library}\steamapps\common\Icarus\Icarus\Content\Paks\
├── pakchunk0-WindowsNoEditor.pak
├── pakchunk0_s1-WindowsNoEditor.pak
├── ...
└── pakchunk0_s28-WindowsNoEditor.pak

Key PAK file: pakchunk0_s18-WindowsNoEditor.pak contains ~80% of mount references.

How Mount Types Were Discovered

Valid mount blueprints were identified by scanning game PAK files for BP_Mount_* references.

The test suite includes PAK verification that scans your game installation:

# Run tests including PAK verification
python test_cli.py

# Skip PAK scan for faster testing
python test_cli.py --quick

Validation Process

1. PAK Scan: Extract all BP_Mount_* references from game files
2. AI Setup Check: Verify corresponding Mount_* AI setup entries exist
3. In-Game Test: Create test mount with blueprint, load game, verify it appears
4. Functionality Test: Confirm mount can be summoned, ridden (if applicable), has correct stats

Discovery Results

Blueprint	AI Setup	In-Game Name	Status
BP_Mount_Horse_C	Mount_Horse	Terrenus	✅ Rideable (wild tame)
BP_Mount_Horse_Standard_C	Mount_Horse_Standard_A*	Horse	✅ Rideable (workshop)
BP_Mount_Moa_C	Mount_Moa	Moa	✅ Rideable
BP_Mount_Arctic_Moa_C	Mount_Arctic_Moa	Arctic Moa	✅ Rideable
BP_Mount_Buffalo_C	Mount_Buffalo	Buffalo	✅ Rideable
BP_Mount_Tusker_C	Mount_Tusker	Tusker	✅ Rideable
BP_Mount_Zebra_C	Mount_Zebra	Zebra	✅ Rideable
BP_Mount_Wooly_Zebra_C	Mount_Zebra_Shaggy	Wooly Zebra	✅ Rideable
BP_Mount_SwampBird_C	Mount_SwampBird	Ubi	✅ Rideable
BP_Mount_WoollyMammoth_C	Mount_WoollyMammoth	Woolly Mammoth	✅ Rideable
BP_Mount_Blueback_Daisy_C	Mount_Blueback_Daisy	Blueback Daisy	⚠️ Companion only
BP_Mount_MiniHippo_Quest_C	Mount_MiniHippo	Mini Hippo	⚠️ Companion only
BP_Mount_Blueback_C	Mount_Blueback	-	❌ 1 HP
BP_Mount_Raptor_C	Mount_Raptor	-	❌ No blueprint yet
BP_Mount_Slinker_C	Mount_Slinker	-	❌ No blueprint yet

How It Works

Parsing Flow

1. Load Mounts.json and extract RecorderBlob.BinaryData
2. Parse UE4 binary format into property tree (FPropertyTag objects)
3. Each property has: name, type, size, value (and nested properties for structs)

Modification Flow

1. Find target property using find_property()
2. Modify prop.value directly
3. For type changes, update multiple related properties

Serialization Flow

1. Serialize each property to temporary buffer
2. Calculate actual byte size from buffer length
3. Write size header, then buffer contents
4. Encode back to JSON format

Safety

• Backups: The editor creates timestamped backups before every save
• Validation: Use validate_mount() to check data integrity
• Game must be closed: Always close Icarus before editing saves

Troubleshooting

Mount doesn't appear in-game

• The mount type may be invalid. Use only types from the "Available Mount Types" table.
• Check for duplicate ObjectFName IDs (clone_mount handles this automatically).

Mount has 0 HP or wrong stats

• Stats are inherited from the mount type, not stored in the save.
• Changing type will give you that type's base stats.

"Failed to load" errors

• Ensure the game is fully closed before editing.
• Restore from backup if needed (.backup_YYYYMMDD_HHMMSS.json files).

Acknowledgements

• CrystalFerrai/UeSaveGame - The UE4 property serialization in this toolkit was based on concepts from this C# library for reading/writing Unreal Engine save files.

License

MIT License - See LICENSE

Disclaimer

This tool modifies game save files. Use at your own risk. Not affiliated with RocketWerkz or the Icarus development team.