Besides the firepower listed above, Great Xia's newly developed Demon Clan Detection Device was the defensive line's true eyes.
These devices could precisely pick up the biological signals and characteristics unique to the Demon Clan, and use the Unified Combat Command System to mark target locations in real time on every soldier's helmet display and every robot's AI combat terminal.
With this system, whenever a Demon Clan creature appeared within detection range, the entire defensive line would know within one second where it was, which way it was running, and how fast.
Hide? Where could they hide?
But all of that was only for dealing with targets on the surface.
Underground... they would have to rely on the Seismic Detectors they had just deployed.
Inside a command vehicle.
Seismic data kept refreshing in a window at the side of the large screen.
A technical soldier wearing headphones worked rapidly at his keyboard.
Explosions were still going off around Freedom Underground City, and the missile and artillery shell bombardment produced a dense mass of noise on the seismic chart.
These interference signals had to be filtered out.
The technician stripped away the waves from explosions, surface collapses, and fracturing permafrost, layer by layer.
A few minutes later, the underlying raw data finally emerged.
His fingers stopped.
On the screen, after all the explosive interference had been filtered out, a cluster of persistent low-frequency seismic sources was moving at a constant speed.
Depth: two hundred to two hundred and fifty meters.
Movement speed: approximately five meters per second.
Direction: from the center of Freedom's ruins, heading straight toward the northwestern section of their encirclement.
The amplitude and frequency characteristics of the waveforms matched the tunneling signals for the "Giant Burrowing Dragon" in the intelligence database by over ninety percent.
The technician