Little history or background is given to this character in the novel; his role is primarily that of a European vampire who becomes an enemy of the main character, Louis de Pointe du Lac. In subsequent novels his character is expanded.
After fleeing from their maker, Lestat de Lioncourt, the Creole vampires Louis and Claudia make their way to Europe to try and find other vampires and answers to the questions Lestat never answered. They make passage through a few countries before they decide to continue their search in Paris. In Paris, they encounter Santiago, a member of the "Theatre of Vampires" led by Armand, a group of vampires once founded by Lestat from the remnants of an ancient vampire coven. The theatre puts on performances involving feeding on terrified humans before a human audience (who think the killings are merely a very realistic performance).
Santiago suspects Claudia and Louis of killing their maker and leads the theatre vampires in abducting and sentencing them to death: Louis is locked in a coffin to starve, while Claudia and her new-found companion Madeleine are exposed to the sun. Louis, who is saved by Armand, takes his revenge by burning the theatre to the ground, killing all the vampires inside, including Santiago.