In ancient Egyptian mythology, the fields of Aaru (/ɑːˈruː/; Egyptian:
iArw meaning "reeds"; altn. Yaaru, Iaru, Aalu), known also as Sekhet-Aaru or the Egyptian reed fields, are the heavenly paradise, where Osiris rules, since he became part of the Egyptian pantheon and displaced Anubis in the Ogdoad tradition. It has been described as the ka (a part of the soul) of the Nile Delta.
The ancient Egyptians believed that the soul resides in the heart; and so, according to their mythology, upon death, in the mythical realm of the dead known as Duat, each human heart is weighed on a giant scale against a feather, representing the concept of Ma'at. Those souls which balance the scales are allowed to start a long and perilous journey to Aaru, where they will exist in pleasure for all eternity. Hearts heavy with evil tip and fall into the crocodilian jaws of the demon Ammit. After this "second death", the soul is doomed to restlessness in Duat.
The souls who qualify undergo a long journey and face many perils before reaching Aaru. Once they arrive, they enter through a series of gates. The exact number of gates varies according to sources, some say 15, some 21. They are uniformly described as guarded by evil demons armed with knives. Aaru is also known as the home of Osiris.
Aaru usually was placed in the east, where the Sun rises, and described as boundless reed fields, like those of the earthly Nile Delta. This ideal hunting and farming ground allowed the souls here to live for eternity. More precisely, Aaru was envisaged as a series of islands, covered in "fields of rushes" (Sekhet Aaru), Aaru being the Egyptian word for rushes. The part where Osiris later dwelt is sometimes known as the "field of offerings", Sekhet Hetepet in Egyptian.