--Gandalf to Pippin, "The Return of the King"
Heaven, in the In Nomine universe, is the celestial realm inhabited by God, his angels and those human souls who achieved their Destiny in life. Demons dare not enter, both because the Light of Heaven burns them and because their presence sounds a false note in the Symphony that draws angels from miles around.
Each Archangel has a special domain within Heaven called a Cathedral, which serves as that Superior's base of operations. These can vary widely, from the peaceful Glade of Novalis, to Michael's training camps within the ancient Grove of trees, to the vast Library of Yves. Some of these Cathedrals also serve to warn or fortify Heaven against attack, most notably the Volcano of Gabriel, the Castle of Zadkiel and the Tower of Blandine (which overlooks the Marches). The angels that serve a particular Archangel will keep their Hearts in his or her Cathedral.
The Higher HeavensEdit
The Heaven that the PCs know is the lowest level of Paradise and the most like Earth. Above is the realm known as the Higher Heavens, where souls can dwell directly in the presence of God. The angels and Archangels are barred from the Higher Heavens unless summoned (although it is rumored that the higher levels may re-open when the War is over). A summons is rare and is last known to have happened in the case of Uriel in the 8th century AD.
Human souls, on the other hand, may freely go to the Higher Heavens using Jacob's Ladder. Most eventually do, though some stay behind to either enjoy the lowest Heaven or to help with the War effort. Some even volunteer to return to the fight on Earth by becoming Saints, if an Archangel will allow it.