by Raymond H Rich
This artifact was brought to earth by the Mi-go and later fell into the possession of the wizard Iraan of Mu. The wizard Zanthu would wield it to claim the high priesthood of Ythogtha. Carved on the surface of the Seal are the Seven Lost Signs of Terror, which can be invoked to command obedience from any creature.
based on material given in “The Offering” by Lin Carter, The Encyclopedia Cthulhiana by Daniel Harms; “The Whisperer in Darkness” by H.P. Lovecraft, and “The Novel of the Black Seal” by Arthur Machen.