Kamo Tharnn, the Possessor, was a librarian, scholar, and seeker of knowledge on the planet Rus, in the Scion system in the Andromeda Galaxy.
The Runestaff was once stolen by the goddess Sif, and used by the Vizier of Asgard to save the life of the dying mortal Jane Foster by infusing the life force of Sif into her.