The Divine Universe

The "Divine" Universe is split into four areas, The Earth, Hell, the Spirit World, and the three divine kingdoms.

The Earth
The earth is where all the living and the mortals live until it is time for them to die.

Hell
The realm ruled by Inferno, otherwise known as Soul Edge. It is the realm where the wicked are punished. It is a desolate, flamy, volcanic area also known as Chaos. Echo Uchiha appears to be some sort of "contract" conecting Hell with the Living World, Earth.

Spirit World
The Spirit World is the realm also called Heaven which is ruled by the goddess, Ha, which is overruled by Saitatsu. It is where the kind of heart go to live in their afterlife.

Telestial Kingdom
The Telestial Kingdom, or the "Earthly Heavens" is the realm of Heaven where the gods such as Rokudou Sennin and Ha reside. They each have their own planet that they live on.

Terrestrial Kingdom
The Terrestrial Kingdom, or known as the "Middle Heaven" is where God (Yhvh) resides as the God of all. The only other people allowed here was Rokudou Sennin, Hikaru Kurosaki, and Byakko Kurohitsugi, who all studied under him. Seireitou Hyuga is also allowed during his training with Rokudou.

Celestial Kingdom
The Celestial Kingdom, or the "Highest Heavens" is somewhere reserved for the Gods of Creation, which are the weilders of the Blades of Absolute Creation: Seireitou Hyuga, Haizo Hyuga, Minkai Zokatakei. When they evolve into Gods, they reside in their respective Kingdoms and rules over all of existance.