Dark drives were a lighthugger-mounted propulsion technology similar to the Conjoiner Stealth Drive, only far more advanced. Developed by humanity with information from Aura, they were completely undetectable, even by Inhibitors. Remontoire explained that the particle exhaust of the engine underwent rapid decay into a non-detectable quantum state.
Unlike its less effective, Conjoiner-designed relative, dark drives were capable of being integrated into existing Conjoiner Drives without causing a massive explosion. This allowed ships such as the Zodiacal Light to upgrade their engines.