For preservationists: The original DVD version with the official 1.01 patch actually works worse than repacks due to SecuROM DRM. The repack scene inadvertently created the most playable version of Onimusha 3 on PC—once you apply the controller fix above.
To fix controller issues for Onimusha 3: Demon Siege on PC (including repack versions), you must address the game's outdated DirectInput system, which originally relied on a configuration menu that is broken on modern Windows versions. Essential Controller & Resolution Patches onimusha 3 pc controller fix repack
You can use XInput Plus to emulate DirectInput. In the DirectInput tab, check Enable DirectInput Output and set the Right Stick to X Rot/Y Rot to fix camera or menu issues. For preservationists: The original DVD version with the
Manually assign your buttons. On many XInput controllers, the default Right Stick may incorrectly act as the Start button until remapped here. Option 3: XInput Plus (For Advanced Remapping) Essential Controller & Resolution Patches You can use
If you have a repacked version of the game that isn't on Steam, you can still use Steam's powerful remapping tools to fix your controller. How to FIX A Way Out Controller/Gamepad Not Working on PC