The Cave of Atman is what Vidyaranya calls that Brahman which the five sheaths of personality are covering.
The five are body, vital force, mind, intellect, and happiness. They don’t form a myth of creation as much as one of deconstruction.
Reasonable self-inquiry says I’m not the body nor it’s vital force. Neither am I the mind–intellect–happiness complex, this tri-lateral reflection of satcitananda.