After failing to blow up that steel demon twice, Herad stopped insisting on killing it with explosives.
The artillery piece began bombarding defensive weapons such as fel cannons.
To keep the defensive weapons safe, Doctor Zizi had built fortifications around them, leaving only firing ports at the front exposed.
Reinforced with boulders and steel beams, the fortifications protected these defensive weapons well.
Mortars with quite respectable range relentlessly bombarded the defensive weapons' positions.
Yet their shells only blasted shallow dents into the fortifications.
Mortars that could be towed by three-wheelers were suited to dealing with lightly armored combat units.
Their destructive power was far too pathetic for demolishing the fortifications around defensive weapons!
An artillery piece was a different story!
Every small increase in the caliber of heavy artillery brought a substantial increase in its power.
120 mm and 155 mm were not even comparable.
That was why mainstream self-propelled artillery used 155 mm guns.
But against stone structures several meters thick reinforced with steel beams, even the considerable power of 155 mm shells failed to do much damage.
The railway gun's massive 380 mm shells hit much harder!
The instant a shell struck a fortification, its weight alone shook the structure.
Green flames flared amid the smoke and dust from the explosion.
That was the flash combustion caused by leaking high-purity fel.
Without that fel cannon suppressing them, the plant army advanced much faster through the surrounding area.
The railway gun fired once every three minutes, unhurriedly blasting defensive weapons and their fortifications apart together.
Doctor Zizi had no countermeasure against the shells coming from an unknown direction.
In fact, even if it discovered where the shells were coming from.
It still had no way to destroy the source.
Its aerial combat units had long since been exhausted.
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