Overall Command was headed by Lord General Du Pres, while each theatre of war was assigned a full general. Tuva Army Group North (TAGN) faced off against the Orks of Snazteef, while Tuva Army Group South (TAGS) faced the Night Lords near Maybourne. Sartano had one army group, Sartano Army Group(SAG) while Merrin's defence was split into Army Groups North and South(MAGN and MAGS). Additionally the Ultramarines landed two companied inearly 11.008M42 and the Blood Ravens and Blood Martyrs also headed the call for aid.
Against Chaos General Du Pres employed almost the same tactic initially.How many Night Lords could there be? How many traitors? Surely they too would succumb to the awesome and limitless forces of the Imperial Guard.
The only thing going for the Imperium in 11.008M42 was the fact that despite multiple enemy bridgeheads, they still controlled 80% of the planet,and their enemies' were fighting each other. The Imperium would once again have to prepare for the long haul only this time, unlike Melberg, Aleph 4and hartak before it, General Du Pres was hoping the Imperial forces on Tarsis Major would hold out.