The Imperial counter-attack did not take long to arrive. Mechs and legionaires were soon deployed and sent to combat the advancing Federal grav troops, but it was too late to destroy the beacheads. The grav troops had already paved the way for the arrival of regular forces, and the Federal aerospacial force was relentlessly pounding Aresian forces with high explosive ordinance. Seeing the heavy resistance in urban centres such as Lupus Gate, Black Eagle high altitude megabombers were sent from space to conduct bombing raids on built-up areas. The Black Eagles were merciless, and carpet-bombed large areas of Lupus Gate with thermobaric explosives, regardless of structural damage and civilian losses. The death of civilians in the first stages of Plan Thunder was deemed "unfortunate but unavoidable". Besides, the Imperium had shown little mercy to Federal civilians during the Core Wars.

Meanwhile, on the ground, Federal forces were attempting to outmanoeuvre and encircle Aresian forces. Aresian artillery was posing a major threat to Federal operations, and a large part of the aerospacial forces was sent to try and take out this threat. Aresian forces, protected by their energy shields, soon found themselves facing a new and insidious weapon: the mole missile. The mole missile had been developed as a counter to Aresian shields and shielded infantry, and it was a high explosive missile designed to drill through the ground and re-emerge inside the protective boundaries of the enemy's energy shields. There was also an anti-mech version designed to fly out of the ground and hit the enemy's walkers in their vulnerable belly area.

Federal ground forces fighting in areas like Lupus Gate received support from T-180 Massalia siege tanks firing thermobaric shells and fusion bombs capable of knocking down entire buildings with one well-placed shot. The armoured vehicles deployed there were also equipped with the new EnDef energy shield that helped the tanks and IFVs to withstand Aresian enery weapon attacks. Federal infantry, especially Ming'hala specialists and Nazcari scouts, would often have to outflank enemy armoured units through buildings before planting fusion bombs or shooting anti-mech missiles at the Aresian walkers' legs.

Meanwhile, in the skies of Claustrum, the sinister shape of a skyship appeared, deployed from orbit. As soon as it was fully deployed, its coil-gun and missile batteries joined the deadly deluge of fire raking Lupus Gate.