An Arae-Shrike was a unique form of electronic warfare "spoofing" technology utilised exclusively by the Legio Custodes, the elite bodyguard of the Emperor of Mankind, during the Unification Wars, Great Crusade and Horus Heresy eras of the 29th through early 31st Millennia. It is not known if this forbidden technology is still available to the Adeptus Custodes of the 41st Millennium.
The Arae-Shrikes were ancient devices of the Dark Age of Technology which twisted and distorted electromagnetic signals. This counterintelligence technology was considered blasphemous in principle and arcane function by the ancient Mechanicum, and persisted only in the hands of the Emperor's retinue. By the use of malifica-djinn and hostile blight-code, they perverted the data-readouts of unshielded Cogitators and telemetry plotters with lying reports and malign falsehood, and what they could not deceive, they simply blinded and deafened with a shrieking multi-frequency cacophony.
Ancient blight-code relays with the ability to pervert enemy Cogitators and Auguries as part of the divine mysteries of electronic warfare were the subject of myth and baleful legend among many clades of the ancient Mechanicum. Utilised exclusively by the Orion Assault Dropship, the dedicated super-heavy assault dropship of the Legio Custodes, the Macro Arae-Shrike was fitted to all patterns of Enyalus super-heavy flyers, which were even more effective than their smaller counterparts. While they were of no use in stealth operations, for the distortion they created forewarned the enemy of the approach of the Emperor's servants, in open warfare they obscured the exact position of the craft and foiled attempts to intercept its arrival with any accuracy.
- The Horus Heresy - Book Seven: Inferno (Forge World Series) by Alan Bligh, pg. 243
- Forge World - Legio Custodes Orion Assault Dropship Rules (Download)