Nephthys is the Goddess of all that is hidden, both within and without the human soul. She represents the realms of dreams, and the dark places within the mind. For this reason she was, and is, often called on to aid with divination, most commonly by means of a dark mirror or scrying mirror as it is also known.
In ancient Egypt she was known by the name Nebet-Het, (Nephthys being her name in the Greco -Roman period). In Kemetic, the language of the Ancient Egyptians, Nebet-Het literally translates as 'Lady of the Temple', this indicates an obvious connection with priestesses.
Though she's rarely written about, Her role in Egyptian Mythology also indicates her connections with the priestess archetype as well as with the 'in-between places.' It is said that she aided her sister Isis/Aset in the resurrection of their brother, the god Osiris/Asar. Because of this she was also invoked along side her sister Isis in funerary rites as a protecteress of the dead.
But she was also shown to have a dark side... That of the seductress and temptress. Egyptian myths tell us how she seduced Osiris leading to his murder at the hands of her jealous husband, the Dark God Set/h. This myth is rich with hidden meaning, giving us a clear understanding of the character of Nephthys. She is the temptress of the soul (represented by Osiris), who on achieving wisdom baths in the light, joy and beauty (represented by Isis, Osiris' wife).
Nephthys tempts us toward further knowledge, that of darkness (represented by Set), she is our guide into the unknown. As the soul passes through darkness it is transformed into higher existence, just as Osiris was resurrected at the hands of Isis and Nephthys to become the Lord of the Underworld, and master of the hidden knowledge. At his side Isis (light) and Nephthys (shadow and darkness).
Nephthys is the guide of the spirit, much like the Greek Goddess Hekate, who illuminates the hidden paths, and the mysteries of our souls before us...