Drusilla is the former Revered Mother of the Red Church and, despite her apparent old age, one of the deadliest servants of the Black Mother alive. Drusilla failed Mia in her final trial, and it was only after the intercession of Cassius, the Lord of Blades, that the girl was inducted.

Upon Lord Cassius's death near the end of Nevernight, Drusilla succeeded him as the head of the Red Church, becoming the Lady of Blades.