Magnus au Grimmus, better known by his nickname, The Ash Lord, is the Arch Imperator (military commander) of The Society. He was responsible for destroying Rhea with nuclear weapons after its leader refused to accept Octavia au Lune's new authority as Sovereign in 680 P.C.E, sixty years prior to the events in Morning Star.

He is the father of Atalantia, Aja and Moira, and godfather of Lysander au Lune.