The Subtle Affective Deficit Evaluation (SADE) Protocol is a novel scenario-based assessment tool designed to detect subtle deficits in remorse, guilt, and empathy—particularly among high-functioning, manipulative, or psychopathic individuals. This work presents the theoretical basis for SADE, drawing on dual-route models of empathy and contemporary psychopathy research. The protocol includes a comprehensive 30-item scenario checklist, empirically grounded scoring rubrics, and a field-ready administration workflow. Validation data using real-world offender language and expert ratings demonstrate strong inter-rater reliability and convergent validity with established measures. All supplementary materials, including validation documents and operational guides, are included to support replication and further research. SADE is offered as an open, field-deployable tool for forensic, clinical, and research applications.