From Edge of Darkness Wiki
Myrmidon Oath-Tongue
The oath the first Myrmidons took to the General applies to their entire dynasty, and is the reason the Praetorians trust the secretive Proximi more than they even trust one another. The Myrmidon Oath-Tongue is a special code-language learned by Praetorian Mages that incorporates elements of the High Speech and the First Tongue of Spirits. A Myrmidon must obey all orders given in the Oath-Tongue, even to the point of his own death, unless the order is impossible to accomplish.