The Black Forest (also known as the Forest of Shadows) is a forested area that the fairies (among them Lilli) hail from. It was burned down by the RKS in the beginning of Rosenkreuzstilette during the time Spiritia Rosenberg and Lilli were chasing Talos, who had abducted Iris Zeppelin, and were looking for the source of the attack on the castle.

The forest can be seen in the background of the Imperial Training Hall, and as Spiritia advances throughout the stage, the player can see the forest be set ablaze.