Heptet was a snake goddess who participated in the vivid cult and surrounding myths of Osiris in the Underworld. Her main duties were connected to the resurrection of her master and looking after his mummy to secure it for his rebirth into the next world, the "Field of Reeds", looking just like the land along the Nile.
For protection against enemies she had daggers in her hands and the opponent might have been the king's brother Set, who was a constant threat to his eternal life. (See Myth of Osiris).
When she was depicted with a human body (like in the picture left) she wore a snake's head and sometimes also a beard. Like her master the Atef-crown was upon her head too or occasionally just the solar disk and horns with a standing cobra.
A similar looking (and sounding) serpent-goddess was Hertept (or Hetep-Sekhus). In the "Book of the Dead" she was caretaker of Osiris' mummy too and was sometimes seen working in pair with Heptet as two snakes lying under his bier.
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