The magma world beneath the earth!
This kind of place, Reiger isn't completely unfamiliar with.
Not only is he familiar, but Reiger has seen multiple places just like it.
For example, the ruins at the Neutral Zone between Akasha Continent's Ginas Kingdom and Leiblu Kingdom, deep there lies an underground magma area sealing the Fire Dragon King. It was at that location where Reiger first encountered the Ice Maiden, Charity Himalafuzz, from the sanctuary, and almost killed her by striking her into magma.
In the Maze City Orario of the Earth Mistake World, the 44th floor of the underground city also hosts volcanic terrains inhabited by fiery magma demons, although it is not completely filled with lava, the terrain is quite similar to a lava region.
