Many consider Phantasy Star III for the Sega Genesis to be the outcast of the series. Personally, I'm a fan of the game but also acknowledge that it's not perfect. If you're one who thinks they can improve upon Phantasy Star III then here's your chance to finally prove it..

Aridia is a rom editor for Phantasy Star III. It has a mostly-friendly interface that makes editing incredibly easy. No messing with hex editors, decoding values, or any of that. If you can click and type then you can hack away to your heart's contentment.


Main Window

Character Editing

Character Initial Inventory Editing

Shop Editing

Item Editing

Enemy Editing

Level Table Editing

Treasure Chest Editing

Script Editing

Enemy Group Editing

NPC Editing

Scripted Event Editing

Editable Graphics

Tile Editing

Palette Editing

PSIII Easy Edition

PSIII Knife Only Challenge

Fun with Palette Editing


Current Version - Aridia 2.5 - for Windows XP SP3, Vista, Windows 7, Windows 8, and Mono

Aridia 2.5 executable - See the Readme file for the list of changes.

.NET Framework 4+ - If you run Windows Update then you probably already have this.

Aridia is a 32-bit application and has been tested on Windows 7 64-bit without any issues. It has also been tested on Windows 8.1 with one issue - it is unsigned and Windows prompts you for a security exception before it can be run.

Old Version - Aridia 1.6 - for Windows XP, 2000, NT

Aridia 1.6 Windows executable - See the Readme file for the list of changes.

.NET Framework 1.1+ - If you run Windows Update then you probably already have this.

The Aridia 1.x branch is frozen.

Source Code

Source code is available on GitHub.


Phantasy Star III Easy Edition (IPS Patch) - 1.4: "Phantasy Star III Easy Edition" is used to test new features added to Aridia.

Phantasy Star III Alternate Font (IPS Patch): Used solely to test & demonstrate font editing.

Phantasy Star III Knife Only Challenge (IPS Patch): Just what the name implies, the only usable weapon in the entire game is the knife.



Aridia Help

Technical Reference

Notes and source files from mr2, TheKomrade, and myself (raw PSIII hex editing info)

Treasure chest addresses


Aridia was not a solo effort, well the coding was but not discovering the myriad of things that can be edited. I am always looking for contributions, even small ones. If you'd like to pitch in, here are some items I'd appreciate help with:

Palette Identification - If you've seen the palette editing screen then you've noticed the large number of unidentified palettes. I'd love to track down what each one is used for. Gens KMod is pretty handy for this because it can display the palettes currently loaded. From there, it's a brute force effort to match them to one of the unidentified palettes. They tend to be grouped together so it's not extremely difficult to do, just time consuming.

Finding New Stuff to Edit - If you can figure out how to edit something currently not supported in Aridia then I can probably figure out how to add it to the UI. For example, I have a pretty good idea where the map data is stored but haven't yet deciphered how it's stored. Once that is determined, creating a screen to do the actual editing is probably the easiest part.

Testing - I'm actually quite happy to get bug reports. I'm certainly accident prone and would like to know when something isn't working or is producing a result that just doesn't seem right. .

So what's in it for me if I contribute? I can't offer cash or fabulous prizes. You will have the honor of appearing in the credits though. There's also the satisfaction of working on what I intend to be the best ROM editor for any game. Well, at least the best ROM editor for a Phantasy Star game. Failing that, the best ROM editor for Phantasy Star III.


This page uses Lightbox2 by Lokesh Dhakar licensed under the The MIT License.