It was already in the next cave that [Indomitable] proved it’s worth. It was as though the ghosts hit a brick wall when they tried to enter his mind and were then unceremoniously thrown out. That in turn just enranged them even further, and they immediately tried to tear him to shreds in their anger.

Unfortunately [Deathwish] did not work in synergy with [Indomitable] as it did with [Immutable Defense]. The ghosts were rebuffed when they tried to possess him but they weren’t hurt in the slightest. It was a bit of a shame, but still, the mental defense was what he was after at the moment. And it seemed to be even sturdier than to [Mental Fortress] even though that skill was at late mastery.

It allowed him to keep pushing through the caverns, and Zac had a feeling he was nearing the end of the subterranean system on his sixth day in the tunnels. Almost all of the beasts in the dens he visited were possessed by now, and animals were hardly more than lifeless husks that housed the spirits within.

Killing the animals barely provided any energies at all, but it at least forced the ghosts out of the bodies. But the specters were changing a bit as well, and he noticed that some were larger and emitted more chaotic energies.

A few of them also possessed a minor version of the piercing wail, but [Indomitable] blocked out most of the effect from those attacks as well. But the increasing strength of the ghosts also meant that his time wasn’t as relaxed as he had hoped. He still needed to be careful about some of the stronger specters, since they could actually harm him with their physical attacks.

It was somewhere late on the sixth day that there finally was a change in the endlessly repetitive pattern of the cavern. It felt like Zac had walked a whole continent cross-country in the tunnels, and he missed the sight of the sun even in his undead form.

The cavern in front of him hinted at change, but he didn’t heedlessly head into it and instead opted to properly check it out first. It was simply enormous, at least ten times the size of the dens he had rampaged through before this. It was also the first cave that seemed to house not a single beast.

Instead, the floor was covered with huge pillars that seemed to be made from onyx or some black crystal. Zac couldn't tell whether they were naturally formed or if they were somehow crafted. But they looked too even and sculpted to be a natural mineral, having perfectly even sides as they rose up to ten meters into the air.

There were thousands of them, and if they held value like normal Nexus Crystals then he might have a chance to jump straight to the first placement on the Gatherer ladder. However, his eyes barely glanced over the forest of crystals before they found themselves glued at the center of the cave.

Another crystal could be seen there as well, but it was completely different from all the others. It actually floated in the air, and it emitted such an enticing surge of power that he almost heedlessly ran over to it by instinct.

It felt like the stone had some sort of hypnotic power since his eyes kept returning to it after moving away. But Zac knew it wasn’t actual hypnosis, but rather his body craving the power the stone contained just like when he saw the Fruit of Ascension the first time.

The power it emitted eclipsed any treasure he had ever encountered, even the lotus that Abbot Everlasting Peace used. It felt like it held untold secrets, and that if he could just possess it he would explode in power. He would be able to sweep away the Dominators and the Incursions alike, and finally make Earth a safe haven.

But there was a problem. The crystal emitted an extremely dense amount of the insidious aura, and it was to the point that the crystal itself might be the source of the darkness. He had a feeling that if he didn’t have access to his new skill that protected his mental state he would have already fallen to madness just by being in this proximity.

However, he still didn’t believe his body was lying to him. That thing was truly a grand treasure, and Zac had a feeling that his suspicions about the Eastern Trigram Sect to be true. If they found that thing they would likely do anything in their power to utilize the mysterious power it contained, though it had obviously backfired.

Zac wasn’t foolish enough to think that he had what it took to control it if an ancient sect failed, but he was also reluctant to just leave it behind. It was no doubt a treasure that even eclipsed the D-Grade, and even if he couldn’t use it he could sell it or save it until he was powerful enough.

But if this was the source of the darkness then it was odd that there was no protection here. Not a single ghost or possessed beast could be seen, and the tall pillars were the only things around it. But Zac was still wary, and he stayed still and observed the surroundings for two hours.

It cost him quite a bit miasma just to stay close to the cave, and he needed to keep a Miasma Crystal in his hands to counteract the loss. He was forced to continuously imbue [Indomitable] with more energy to counteract the lure of the Core of Darkness, which was what he decided to call the treasure in the center of the cave.

At least nothing had moved in the slightest as he observed the cave, and he had already made a few plans as he waited. He had made up his mind; he would snatch that thing. Of course, if things turned south he would have to let it go, but he refused to leave behind such a treasure without giving it a try.

He had already spotted the exit on the opposite side of the cavern, so he knew where he needed to go. But before he did anything he put on an amulet. Luckily he had brought the amulet that hid his presence from the undead that he got from Ogras, and he hoped that it would at least have some effect in case the ghosts rested inside of the crystals. He also imbued his mental skill with the Dao of Hardness to improve efficiency.

This time he didn’t jump down the five meters from his vantage in the tunnel, but instead silently climbed down the wall, careful not to make a sound. The moment he exited the protective array of the mouth of the tunnel he immediately heard a low humming sound.

It wasn’t from a person, but rather a sound of all the pillars vibrating. Zac had no idea what that could mean, but he was happy if that was the only sound. It could have been a bunch of ghosts wailing instead, but not a ghost was in sight even after he had climbed down the wall.

He didn’t move for a few seconds, afraid he would trigger something, but the droning sound was the only thing that could be heard. So Zac started to silently move toward the Core of Darkness, careful to stay to his pre-plotted path. He was afraid that getting to close to the pillars might trigger something, so he had carefully mapped out the path that would take him to the Core of Darkness while maintaining the highest distance from the crystals as possible.

It was pretty disconcerting to walk between the towering pillars, and it almost felt like he was inside some cursed forest. The darkness both in the atmosphere and the crystal pillars were palpable, and Zac couldn’t help but increase his speed somewhat.

He was loath to stay in this cursed place longer than he had to, so he was almost running as he got closer and closer to the Core. But his fears were suddenly realized as a ghost emerged from one of the crystals close to him. Zac immediately disintegrated it with a quick swing of his axe, but its appearance proved that he wasn’t alone in the cavern.

Destroying the ghost that way only bought him a few seconds, so he immediately started rushing toward the Core, no longer caring about avoiding making any sounds. Two seconds later an enraged wail echoed through the chamber, and that wail brought with it pandemonium.

Innumerable ghosts rose from the pillars, and soon the whole ceiling was blotted out by the specters. There were thousands of them, many emitting even stronger auras than any specter Zac had encountered so far. The worst-case scenario was true; The pillars housed the ghosts like the possessed beasts.

Zac was full of alarm as he rushed toward the Core of Darkness as fast as his legs could take him, and he even pushed miasma into his legs to increase his speed. Luckily he had managed to pass most of the pillars already, and only a few hundred meters remained.

But a storm of ghosts was rapidly descending on him, and Zac immediately equipped his shield and summoned [Immutable Bulwark] and his two passive skills. He held the shield right above his head as he imbued it with the Seed of Hardness.

The ghosts could pass straight through the fractal shield normally, but they were unable to do the same when the shield was empowered by a Dao. They could still pass around it and attack him from the other sides, but it at least lessened the attacks on him a bit.

A few of the larger ghosts were almost immediately upon him, and his miasma was rapidly getting expanded to protect himself from tries to possess him. But not long after Zac started to gain streams of miasma from the ghosts who finally had killed themselves in their frenzied attempts to stop his advance.

But the miasma he gained from [Fields of Despair] was far below what was expended to continuously defend, and Zac knew that he wouldn’t be able to slowly grind these ghosts to death with [Deathwish].

The large ghosts were far too strong. Not only did they manage to rend gashes on his skin that started to bleed the black ichor, but their attempts to possess him also forced him to expend a large amount of miasma. Had it only been the basic ones it would have been a different story, but this seemed to be the place where the strongest ghosts gathered.

He kept putting one leg in front of the other as he ran, and suddenly he was completely unencumbered by any attacking ghosts. Zac looked up with some confusion and found himself staring straight at the Core of Darkness. Desire to touch it almost blocked out everything else in his mind, and his hand even reached toward the shining crystal. But Zac forcibly moved his hand away and quickly averted his gaze with trepidation. That had been too close.

He quickly shot a gaze behind him to find that the ghosts were loath to approach any further. Suddenly one of the smaller ghosts wailed in rage and flew forward to bite Zac. However, it didn’t even get halfway to him before it suddenly disintegrated, and its particles were sucked into the crystal.

Zac was surprised since he wasn’t expecting it to feed on the ghosts. He even started to consider carrying it in his arms as he fled to the exit of the cave. It would keep even the largest ghosts at bay, providing with safe passage. But he shook his mind after a bit. He didn’t dare to actually touch that thing since he had no idea what would happen.

This thing might be the source of downfall of a sect, and running around with it in his hands was tantamount to suicide. He quickly took out a chest wrought of some unknown metal instead. It was pretty large and could contain at least two cubic meters. Inscriptions covered most of the thing and it weighed almost half a ton from his approximation.

It was something he had looted from one of the summit palaces. A bunch of valuables that emitted strong energies had been stored inside it, but before he opened it he didn’t sense the slightest fluctuations. So Zac hoped it would be able to contain at least some of the aura of the Core of Darkness, giving him enough time to stow it away into his Cosmos Sack. Since that place was a separate space he didn't think it would be able to cause any problems as long as he stored it.

He ignored the increasingly enraged screeches and wails of the ghosts as he lifted the chest, carefully maneuvering it to enclose the Core. The moment it was fully encapsulated Zac quickly snapped the thick lid shut, but before he could put the chest into his Cosmos Sack a wave of some unknown force cascaded out from the Core of Darkness and passed right through the chest.

Zac only sensed [Indomitable] activate, and immediately fail, before his vision turned black.