[Advanced Death Magic: Soul Deprivation Field]
In an instant, a complex magic circle unfolded beneath Hel's feet. Any spherical mechanical soldier that entered its range froze completely mid-motion, rolling away limply under the force of inertia.
If a sorcerer proficient in death magic had been present, they would have immediately noticed that every mechanical soldier stepping into the array lost the faint trace of soul sealed within its core at that very moment.
But that wasn't the end of it. As more and more spherical mechanical soldiers collapsed around Hel, streams of pale-blue soul energy began to rapidly converge within the magic circle.
Little by little, those scattered fragments of soul built up—until even though each individual soul was weak, the total gathered energy became an astonishing amount.
However, if this continued unchecked, those dense waves of soul energy would soon overload the formation and erupt into a devastating Soul Tide.
Hel, Arwin, and Sebas might not need to worry about such a surge—but the miners certainly did. Under the force of a Soul Tide, their minds could easily shatter, leaving them as nothing more than empty shells.
Thus, Hel raised her left hand, joining it with her right before her chest.
[Advanced Death Magic: Philosopher's Stone Creation]
In an instant, countless threads of soul energy twisted together in her palms, weaving into form.
Soon, a thumb-sized crimson crystal materialized in midair. Its translucent surface glimmered with golden motes of light flowing slowly within, dazzlingly beautiful and dreamlike.
The Philosopher's Stone—known as the "universal energy source."
Formed entirely from the purest essence of souls, it could be converted into any form of extraordinary power—life force, elemental energy, or otherwise.
Yet its greatest purpose was to strengthen the soul itself.
Directly consuming an elemental crystal required a full week to digest, and even longer for the user to fully adapt to their newfound power. During that time, the elemental energy would gradually reinforce the soul, allowing it to match the user's enhanced strength.
Compared to that, the process of strengthening through the Philosopher's Stone was far more efficient.
For Arwin and the other physical fighters, this distinction didn't matter much. But for Hel, a death witch—and a transmigrator whose soul was inherently powerful—it made all the difference.
And for old Sebas, it was even more critical.
As a magic user, the strength of his soul was paramount.
Moreover, the undead creatures Hel created through necromantic sigils possessed extremely chaotic souls—barely intelligent, driven only by the instinct to kill.
But what if she could replace those souls with new, purified ones?
Then Hel could immediately create undead with intelligence and will.
The difference between mindless and sentient undead was like heaven and earth.
For example, Hel could easily send Arwin with the skeletal knight corps to carry out missions independently. But she would never trust the berserker bone warriors to explore ruins alone.
However, replacing souls required immense soul strength—precisely where the Philosopher's Stone came into play.
Hel had long planned such an experiment but lacked both the opportunity and materials. Back then, even if she had suitable souls, she would have used them to summon more undead for combat power rather than "waste" them on refining Philosopher's Stones.
But now, the situation was perfect for implementing that postponed plan.
Wave after wave of spherical mechanical soldiers poured endlessly from the passage, as if without end.
By this point, Hel had ordered all undead and mechanical sentinels to retreat to her position. The team had shrunk once again—every third-tier skeleton swordsman was gone, each one picked off by the lurking hunters among the enemy ranks during the first clash.
Several of the third-tier mechanical centurions had also been destroyed, while the rest bore varying degrees of damage.
Those above the third tier, however, remained largely unscathed.
The enemy's fourth-tier forces hadn't joined the battle yet, and the third-tier snow elf hunters alone couldn't penetrate their defenses—in fact, some were even slain in counterattacks.
Thus, Hel ordered her five remaining fighters of third tier and above to hold the front line before her.
The other mechanical centurions were reduced to laborers, tirelessly hauling the soulless corpses and wreckage toward the rear tunnel.
Meanwhile, at the great gate, Hel's main body was busy at work.
The original entrance—ten meters high and five wide—had been reinforced under her command, now reduced in size by nearly half.
She rebuilt a five-meter-thick wall inside the doorway, leaving only a narrow corridor barely wide enough for a single person to pass through.
At the end of that passage—on the side facing the ruins—she sealed it completely with basalt bricks, leaving just a thumb-sized hole.
Hel now extended the finger wearing her spatial ring through that small gap, collecting the corpses and wreckage her minions brought her.
It was all about safety.
If a powerful enemy appeared, she could instantly seal the hole, then fill the passage completely, cutting off pursuit entirely.
And if no such threat arose, she could simply reopen it later—hardly a difficult task.
Time slipped by. Her spatial ring had filled up several times already.
After the second time it overflowed, she directly opened a gate to the Undead Space beyond the wall.
By now, she had no idea how many bodies and wrecks had been gathered—but judging from the size of the Philosopher's Stone, it contained at least twenty thousand first-tier souls' worth of energy.
That meant the enemy had already deployed tens of thousands of first-tier combatants just to stop them in barely half a day—a staggering display of resources.
Even Hel had to admit, their wealth was impressive.
Pity they lacked brains.
The range of her two death spells wasn't that large, and she couldn't move while casting.
If not for her clever use of terrain—and the enemy's suicidal recklessness—she could never have achieved such results.
She didn't know how long had passed, but eventually, the relentless advance of the cannon-fodder army began to slow.
Hel knew what that meant—
the reinforcements they'd been waiting for had finally arrive