The Bottommost Depths is a location in Final Fantasy IV: The After Years. It is the deepest section of the True Moon, located beyond the Depths and is where the party meets The Creator, who emerges when they destroy his pod. He reveals the true nature of the Crystals and tells them the Earth will be destroyed because they have failed to evolve enough to satisfy him, after which the party attacks him.
Afterwards the mechanics of the Creator's pod affect his mind and he transforms into a grotesque monster. The party, empowered by the prayers of the Earth, use the Crystals of their world to destroy the darkness protecting him and destroy the Creator. The moon begins to collapse and the party flees back through the Depths as the Creator chases them. One by one, the Creator's Maenads sacrifice their lives to hold him off and allow the party to make it back to the Lunar Whale and escape the moon.