Ys IX: Monstrum Nox/Walkthrough

When starting a new game, you need to select a difficulty setting. You can change the difficulty anytime in the Options menu, but if you raise the difficulty above Hard mid-playthrough or lower the difficulty below Nightmare, you cannot earn the Nightmare Survivor achievement/trophy.

Save data
If you have save data from Ys: Memories of Celceta or Ys VIII: Lacrimosa of DANA, you have the option of acquiring a bonus accessory from each game.
 * Celcetan Wreath (Ys: Memories of Celceta)
 * Old Seal Ring (Ys VIII: Lacrimosa of DANA)

The game only checks for save data in the beginning of a new game. For the PC version, the save data must be located in %userprofile%\Saved Games\FALCOM.