Sigil ring
From Tardis Wiki, the free Doctor Who reference
The Sigil ring was the ring of the Great Vampire recognised by vampires all over the cosmos. The ring was made of the command circuitry of Rassilon's lead Bowship. Ripped out of the deck by the Great Vampire, it could reactivate any of Rassilon's personal technology. The Time Lady Ruath found it in a book made of human flesh bound into a real spine. The ring was silver, and a sign of the Cult of the Vampire Rassilon. (MA: Goth Opera)
