The Blades of Reason is an ancient and horrific device utilised by Interrogator-Chaplain Asmodai of the Dark Angels Space Marine Chapter. This ancient and fell device is full of arcane cruelty and the sorrow of Mankind. Its many sharply honed and well-polished blades are etched with scriptures of repentance in the tongue of Old Caliban, and criss-crossing the weapon's head are cables and fine neural-wires, mystic science that amplifies pain to agonies beyond endurance. With an expert using this device, all but the most resilient of prisoners will very quickly divulge any information they have. Utilising this archaic weapon of torture, Asmodai attempts to extract confessions from captured Fallen Angels during interrogations in an attempt to save the doomed prisoner's soul through his expert and painful ministrations.
- Codex: Dark Angels (6th Edition), pp. 55, 92
- Codex: Dark Angels (3rd Edition), pp. 4, 17
- Index Astartes II, "For the Emperor!: Space Marine Chaplains", pg. 59
- Warlords of the Dark Millennium - Asmodai (Digital Edition)