Forest of Illusion

The Forest of Illusion was a forest surrounding the Five Lakes of Mount Fuji. Vegetation in this area was very dense and not easily traversed. The forest concealed the entrances to many subterranean caves on the shores of the five lakes. One of these contained the Shrine of the Mirror of Life.

Trivia
The forest is almost certainly a pseudonym for the real life forest of Aokigahara, a forest which is historically associated with demons in local legends and surrounds the Fuji Five Lakes area in real life.