Complex sentence: At present, Nanny and the Orphan-Maker are at large, but and it was revealed within the "Slingers" series that both she and the Orphan-Maker were responsible for killing Ricochet's mother.
Split into simpler sentences: At present, Nanny and the Orphan-Maker are still at large. It was revealed within the "Slingers" series that they were responsible for killing Ricochet's mother.