The Union's instrument of internal security, tasked with rooting out treachery and extracting confessions from those suspected of it. The Inquisition operates under the authority of the Arch Lector and employs Practical methods - torture, imprisonment, and the systematic destruction of suspects - justified by the necessity of protecting the state. Superior Sand dan Glokta is its most effective practitioner and its most self-aware one: he applies his methods with professional precision while remaining entirely clear-eyed about what he is doing and what it has cost him. The Inquisition is one of Abercrombie's central satirical targets - an institution that perpetuates itself through the fear it generates and the confessions it produces, regardless of their truth.