"What... the underworld?"
Adalbert blinked.
He was a little slow to process it.
Terra's myths of the underworld were not well developed. Perhaps because some legends had been lost in the Calamity of Falling Skies, the more common folk belief nowadays was the "heaven and hell" system, while the vast majority of Ascenders knew perfectly well that the soul's final destination was to return to nature's cycle.
Other than the Nethertrace Order, few people took an interest in an "afterlife"—seeking comfort and pleasure in this one life was the absolute mainstream.
Ian accepted the thick stack of conceptual calculation blueprints from the young Undead Monarch and scanned the thoughts and calculations written across them.
Adalbert's line of thinking had indeed been optimized from Ian's original idea.
At first, Ian had thought to use artificial souls, gathering them in sufficient numbers to activate the spirit-machine core.
Ordinary people truly could not, like those at the Second Energy Level or Third Energy Level, trigger the spirit-machine core's active offensive capabilities. But they could still drive Origin Matter spiritual-energy conversion and activate spiritual-energy shields.
Of course, the most crucial point lay in a powerful "energy furnace core"... and that was actually the easiest part to solve.
Whether it was a leyline furnace, the Aether Furnace Core technology Ian already possessed, or the "Nethercrystal Engine" beneath Radiant Haze Lake, all could be used.
But the problem with this idea was that activating a spiritual-energy shield required time to gather enough people.
It was manageable against natural disasters. For instance, a great storm would at least show signs an hour or so in advance. That was enough time for local residents to gather at key shelters and activate the spirit-machine core.
But if it were an ambush like the one Ian had launched when he