Astra Militarum: Auxilia (pb)

Auxilia is an Astra Militarum novel by Russell Zimmerman, available here in paperback.

Castellan-Colonel Roane must turn an ill-supported force built around an abhuman clan into a fighting regiment. Facing a hostile commissar, neglect from the Departmento Munitorum and the outbreak of civil war, the young Cadian commander discovers how difficult leadership becomes when allies would rather see his unit fail.