I've seen here and there people who asked where to find the game. It can be found... here !
● Game Client
・setup-1a.bin
・setup-1b.bin
・setup-2a.bin
・setup.exe
・ill_manual.zip (entirely in japanese)
Checksum :

This is the JP PSU:AotI client, the one that was freely distributed by SEGA, when the JP PSU servers were still online. That's why I continue to distribute it - although I don't have the right to do so - until SEGA takes measure to make me stop. Which I hope will never happen, I don't think that's reprehensible from a moral point of view.
To install the game, you just have to downlod in a same folder the four first files and keep their original names.
● AE(/F/G) Patch (mandatory)
This patch :
- automatically translate the game (text only) in (American) English¹ ;
- allows you to play offline ;
- allows you to play online on the unofficial Clémentine server ;
- fixes some monster hitboxes (cf. this news) ;
- corrects a visual glitch on one of the Alterazgohg's attack (this bug only existed in the JP ver. of the game) ;
- replaces the loading icon used in 4:3 and 5:4 aspect ratios resolutions by a better one used in the CβT ;
- replaces the loading icon used online in 16:9 aspect ratios resolutions by the one made by Clémentine ;
- includes all JP 2.0014.30 contents (1st, 2nd & 3rd Sup' Up' ; basically all contents introduced to the PSU series by the Portables game up to PSP2i)
■ If you're a little bit computer savvy :
・PsuIlluminusInt (*.7zip)
This patch is easy to use : once you have installed PSU:AotI, simply extract the content of the *.7z files into the root directory of the game (by default, "\SEGA\PHANTASY STAR UNIVERSE Illuminus\"). It should look like to this :

Then, just execute the batch file (PATCH.BAT), wait a few seconds and you're done !
Use the launcher to play offline, to play online, to open the options menu...
■ If you're "dummy" (or extremely lazy) :
・PsuIlluminusInt (*.exe - self-extracting 7zip archive)
To open image in a new tab without leaving this page, click on it with your mouse wheel.
1. Download it and put it where your game is installed :

2. Double-click on it :

3. Don't change the path destination, simply click on the "Extract" button and wait :

4. Once the extraction is completed, it should look like this :

5. Select the "PATCH.bat" (it may simply be called PATCH if you hide file extension) :

6. Launch it, wait (and press a button when you're prompted to do it) :

7. Now, it should look like this :

8. That's all. You don't have to edit anything (unless you want to play in French or German), to download a specific file to play online on Clem', to erase file/archive that became useless once the game has been patched, etc..
Simply launch the online(.exe) from here, or use the shortcut that has been created on your desktop during the game installaton :

Select "Options" to set your game, "Story Mode" to play to the offline mode, "Network Mode" to play online on the Clementine servers, etc...
● Custom Resolution
If you don't really understand how to customize your *.exe - although this tutorial is clear - or if you're too lazy to do so ; you can use these ready-to-use *.exe ! Simply replace your PsuIlluminus.exe, PsuIlluminusOff.exe & PSUC.exe by the one provided below and set your game to 1280x720.
・1280x720 (backup)
・1366x768
・1600x900
・1920x1080
・2560x1440
・3440x1440
・3840x2160
The problem of playing in custom resolutions is that the map and mini-map are broken. If that really bother you, and until someone or myself find a proper fix to this problem, you can use these another *.exe that disables the mini-map and the compass (on the mini-map and the map ; the same compass is used for those two things) :
・1366x768 (without mini-map)
・1600x900 (without mini-map)
・1920x1080 (without mini-map)
・2560x1440 (without mini-map)
・3440x1440 (without mini-map)
・3840x2160 (without mini-map)
● Patch 2.0014.30
Only for those who know what they're doing.
I just ask you two things :
1. Although the patch must work correctly, I can't be sure at 100%. If you notice something strange, please, report it, I'll get it fix'd ASAP.
2. Because of this, don't hotlink those dl links : Mega doesn't allow me to keep the same download link when I update the patch. Link this thread instead. BTW, by consulting this thread, people can know if their game is "up-to-date" or not.
※ Usage of Google Chrome is recommended. While download should work with other browsers, it isn't guaranteed.
● Bonus - Phantasy Star Universe
・Game Client :
・setup-1a.bin
・setup-1b.bin
・setup-2a.bin
・setup.exe
・psu_manual.zip (entirely in japanese)
・Offline AE(/F/G) Patch ¹ (OR self-extracting 7zip archive)
¹If you want to set your game in French or German - although it probably never be (fully) supported by D&H or Clem' for PS: AotI - you've to manually edit your *.ini. Press Windows + R then input (without the quotes) :
"%LOCALAPPDATA%\SEGA\PHANTASY STAR UNIVERSE\Psu.ini" for PSU
"%LOCALAPPDATA%\SEGA\PHANTASY STAR UNIVERSE Illuminus\PsuIlluminus.ini" for PSU :AotI
Then replace the "AE" on the "Language" line by the letter corresponding to the language you'd like to use ("F" or "G"), and don't forget to save your changes.