Nephthys meaning ‘lady of the house’ in the sense that house represents the sky. The daughter of Geb and Nut and sister to Osiris. She was also the sister / wife of Set. In the early times of Nephthys' being, she was seen as the female counterpart to Set. She was also close to her sister Isis as when Osiris’s body was scattered around the world by Set, she went in search with Isis to recover the parts.
Throughout all accounts of the Book of the Dead, Nephthys stands with the deceased as a friend and probably inherited this trait from an earlier form of fertility goddess. Later in history Nephthys obtains the name Nebkhat (‘The Lady of the Gods’) Nephthys is present (usually behind Osiris) at the Weighing of the Heart Ceremony. Nephthys is different to her sister in that she was depicted as a bird of prey (the Kite) and was associated with putrification on the flesh and death. She was seen as the passing of all flesh and a necessary process to attain a higher state in the afterlife. This said, Nephthys is not the complete inverse of her sister as she supports Isis on her quest for Osiris and also helps Ra in his nightly journey across the sky.