The highest(?) level of the Grave Pillar, the teleporter to the Hanging Garden above is located here. Ypsilon is confronted for the final time after his kidnapping of Kohaku, but he's quick to destroy the teleporter to ensure Copen can't proceed. In Hard Mode...
This stage is effectively a versus mission, as following a cutscene the boss battle immediately begins.
Although this is the highest floor accessed within the Grave Pillar proper, the mission select map indicates that it is below the actual top of the tower.
Null in the background twitches in normal mode, but remains stationary in hard mode, reflecting her status as being the teleporter to the Hanging Gardens.