Members of the Khor herd are pejoratively referred to as Marrow by the Consortium . It is said to have started when [CONSORTIUM OFFICIAL] claimed the herd were "nothing more than organic automaton - the pulp within the bone."
The "bone" in this case refers to the EXO - a heavy, exoskeletal suit designed for direct combat. The "organic automaton" reference highlights the way the Marrow engage in conflict. The herd is an oppressed majority, living under the veil of the Consecrated mythos. To the marrow the battlefield is viewed only through goggles displaying augmented reality of their opponents. Ignorant of the advanced tech, the Marrow believe they are fighting to protect the herd, fighting to protect the Consecrated and the god-king they serve.
Driven by fear (a powerful form of psionics) the marrow are pawns in the Khor clerisy's battle for resources and wealth.