When Lestat discovers that Mona Mayfair has a Taltos child, Morrigan, who grows into a woman almost instantly, and that Morrigan has run away with another Taltos, the ancient Ashlar, to his secret island where they have four children, Lestat begins referring to his own fledgling Mona as the Little Grandmother.
The sobriquet appears in Blood Canticle (2003). For more perspectives on the “Little Grandmother” sobriquet, read the Alphabettery entries Ashlar, Lestat de Lioncourt, Mona Mayfair, Morrigan Mayfair, Quinn Blackwood, and Taltos.