The Nun II is the ninth overall installment in The Conjuring franchise but the third chronologically, with the Nun movies intended to serve as something of a prequel to the events of The Conjuring series.
However, the movie reveals that Sister Irene and Lorraine Warren are from the same bloodline. This was revealed when the movie explored Sister Irene's heritage, and it showed she is a descendant of Saint Lucy. She then has visions of people in Saint Lucy's bloodline, and one of those people was Lorraine Warren.
