Their existence is first discovered prior to M19: Incursion, after intercepted Pirate messages were decrypted. Initially, the Galactic Federation assumed there was only one device, and its destruction would expose the Doomseye. However, the Doomseye remains undetected after its destruction. Further decryption of the Pirate messages gradually reveals that each planet had a transfer device. The Federation Force is tasked with destroying the last two in M20: Insurrection and M21: The Core.