While waiting for the Dreadlords or their subordinates to step into his trap, Archlich Kel'Thuzad developed a deep interest in this mysterious area within Tirisfal Glades.
He stood in the camp, an ancient tome floating before him. The book, supported by his magic, hovered in mid-air and turned its pages according to Kel'Thuzad's thoughts.
To one side of the book were the refined energies of the glades, divided into three types: Arcane, Holy Light, and Shadow.
The Archlich was slightly surprised to find that the purity of the origins of these three energies was exceptionally high, surpassing any spellcaster or user of such energy he had ever encountered.
This discovery filled Kel'Thuzad with questions, so he sought out ancient texts, attempting to find the source of these three energies.
At the same time, he recalled Arthas telling him that this area held some kind of secret, but since Arthas had not directly told him, he could not express his confusion to the Lich King.
However, this did not stump the Archlich; as a former member of the Council of Six in Dalaran, his mastery of magical research was top-tier even within Dalaran.
Coupled with the integration and application of the knowledge imparted by Ner'zhul, the Archlich's power and knowledge reserves far surpassed his previous levels after being resurrected by the power of the Sunwell.
Without much effort, he captured and refined the energies in the glades, wanting to trace the true source of the mysterious influence on this land.
The book turned to a certain page and suddenly stopped. Kel'Thuzad let out a soft chuckle, exclaiming in wonder:
"Interesting."
After a brief moment of thought, Kel'Thuzad's laughter ceased, and his bony finger slowly traced across the page.
"Thassarian, come to me."
Thassarian, who was monitoring the movements around the town, heard Kel'Thuzad's summons. He handed his task over to the nearby skeleton sentinels and set off towards the Archlich's location.
"What is it, Lich?"
"Take off your gauntlet and show it to me," Kel'Thuzad made a peculiar request.
Thassarian stared at Kel'Thuzad for a moment, then removed the gauntlet from his right hand and handed it to him.
With a flick of Kel'Thuzad's finger, the saronite plate gauntlet floated before him. The Lich, with a solemn expression, moved a wisp of Shadow energy onto the gauntlet's surface.
Upon contact with the saronite gauntlet, that small wisp of energy seemed to come alive, rapidly trying to burrow into the armor gauntlet's interior.
Although it happened suddenly, Kel'Thuzad did not allow this wisp of Shadow energy to completely escape. With a gentle tap, he confined it, returning it to its place among the other two energies.
Strangely, the energy that had been lively and squirming like a worm immediately quieted down, losing its original vitality.
Kel'Thuzad stared at the plate gauntlet, which seemed to have become slightly darker than before, and asked Thassarian again, "Is your sword also made of saronite?"
After several more experiments, Kel'Thuzad discovered that these Shadow energies only reacted with items made of saronite, and upon contact, the quality of the saronite would experience a very subtle improvement.
However, at the same time, the inherent corrupting influence within saronite would gradually increase until, after reaching a certain threshold, even the undead would not be immune.
Undead under Kel'Thuzad's control, after using contaminated saronite products, would rapidly lose control, becoming insane and violent, even attacking their master.
After casually turning a few skeletons into piles of bones, Kel'Thuzad gained an initial understanding of this Shadow energy.
It seemed to originate from the same source as the Shadow power that formed the saronite ore, with the difference being that this power possessed a high degree of activity.
Kel'Thuzad's extensive knowledge made him understand that active energy forms when the owner possesses extremely strong power and their self-awareness is hindered, causing their consciousness to diffuse into the energy itself.
This situation occurs when the energy's owner dies or falls into a deep sleep.
While in Dalaran, he had seen active fire, water, air, and even soil, but active Shadow energy was something he had never encountered before.
Regardless, whatever lay behind this energy must be extremely dangerous, as Kel'Thuzad had witnessed countless mages suffer backlash from active energy due to improper handling.
Furthermore, Shadow energy was the most dangerous kind, far more perilous than elemental energy.
Thassarian's gauntlet and longsword had only suffered a slight erosion, and the accumulation of their corrupting nature was almost negligible. The quality of the metal itself had improved somewhat, which was an unexpected benefit.
As for the saronite ingot used for subsequent experiments, Kel'Thuzad completely destroyed it with magic.
Because on that evil ingot, there were even dense, continuously writhing Shadow tendrils, Kel'Thuzad realized that continuing would likely lead to unpredictable consequences.
If he weren't currently on a mission, preparing for an experiment wouldn't be impossible, but Arthas's order was for him to hunt down the Dreadlords and reclaim Naxxramas. If he caused trouble due to his curiosity, he would certainly face a grim outcome.
In addition to analyzing the Shadow energy, Kel'Thuzad also conducted a simple analysis of the Holy Light and Arcane energies. However, this time, due to a lack of good experimental material, besides learning that these two energies could harmoniously and stably merge and suppress Shadow energy, he did not obtain any more useful information.
Nevertheless, none of this prevented the magically proficient Kel'Thuzad from utilizing the environmental advantages to increase his chances of completing this mission.
"Demons are masters of wielding fel and Shadow—but that doesn't mean they can use these two powers recklessly; they are the most dangerous energies in the cosmos."
Kel'Thuzad summoned the skull left behind by a deceased skeleton soldier, holding it in his hand. A large amount of Shadow power, condensed by him, was absorbed into the skull.
Once the skull reached its maximum energy capacity, Kel'Thuzad placed a magical seal upon it and handed it to Thassarian.
"Use this power wisely; it can play a crucial role at certain times."
Kel'Thuzad's upper and lower jawbones moved twice. Although there was no sound, Thassarian understood that the Lich was laughing.
"Crush this skull, or erase the magical seal on it, and the energy within will burst forth. As for how to use it, that is your problem—of course, it can only be used once; this is just the skull of a common cannon fodder, unable to bear too much power."
Thassarian raised the pitch-black skull. In its empty eye sockets, some unspeakable, horrifying presence seemed to be gazing at him, and various thoughts constantly arose in his mind.
As a Death Knight, he quickly suppressed the temptation of the Shadow energy. Thassarian hung the skull on one side of his belt, adding another seal with runes.
"A wise move, Death Knight. Be careful with this power; it could also harm you."
Kel'Thuzad turned around, satisfied. He then connected with his master, Arthas, because there were some matters he needed to report to Arthas.
Soon, he received Arthas's response.
"What happened, Kel'Thuzad?"