Regarding the entanglement with the tails following behind him, Dong Tianyu actually did not pay too much attention. After entering the Companion Spiritual Treasure, Dong Tianyu directly dumped the Mysterious Cores that he had been selling over the past few days from his Storage Space.

As soon as these Mysterious Cores made contact with the ground of the Companion Spiritual Treasure, they instantly merged into it. If it weren’t for this situation, the little space in the Companion Spiritual Treasure would have been filled with those Mysterious Cores many times over.

Perhaps due to Dong Tianyu’s command, no matter how many Mysterious Cores it consumed, the size of the Companion Spiritual Treasure did not increase in the slightest, remaining in its initial smallest form.

While Dong Tianyu was dumping out the Mysterious Cores, he also paid attention to his surroundings.

Perhaps because the Magic City’s first base had frequent interactions with outsiders, unlike Magic City’s third base and Lakeside Base, there weren’t many Raft Forms of Companion Spiritual Treasure surrounding the base, intending to use this method to disperse those fish-like creatures lurking beneath the water surface.

Dong Tianyu, observing his surroundings, inevitably noticed the few tails following him.

Originally, Dong Tianyu did not want to bother with these little tails, but then he suddenly remembered the Realm of the Undead in the Cave, which he had nearly forgotten. Since someone was proactively coming to him, it was a good opportunity to conduct an experiment.

Since the System upgraded and Dong Tianyu transferred the Cave to a Different Dimension Space, making it his personal space, he actually had not been as attentive to the situation inside the Cave as before and often neglected it.

The main reasons were twofold: first, due to the Undead Disaster, Dong Tianyu had little free time, and after starting Cultivation, he devoted most of his time to it, so naturally, he also paid less attention to the situation inside the Cave.

Of course, another reason why Dong Tianyu did so was that the Canaries within the Cave managed it quite well, so Dong Tianyu naturally did not bother much about the situation there anymore.

At that time, due to the Undead Disaster, out of curiosity, Dong Tianyu sectioned off an area inside the Cave specifically to contain Undead Creatures.

Actually, most people have a misunderstanding about Undead Creatures. Many believe that Undead Creatures do not need to eat or drink, especially Skeletons, which are considered a perfect model of tireless labor.

After all, even intelligent robots need to combat wear and tear and require charging.

In the understanding of many, Undead Creatures need nothing and can work endlessly without stopping.

However, they are not aware that Undead Creatures are not without consumption as they think. It’s just that the scenes where Undead Creatures appear are either early death or the surrounding environment has the materials they need.

Just as humans need to eat and robots need to charge, the substance that Undead Creatures normally consume is either death energy or Soul Power.

Undead Creatures appear either in eerie, terrifying wastelands, or in the heavy death energy of cemeteries, or amidst battlefields.

Thinking of these scenes, high-level Undead usually appear in wastelands. These wastelands are likely named as such perhaps because of those high-level Undead that devour the souls of living beings.

Those wandering in cemeteries are mostly low-level Undead, which simply need to absorb the death energy there to sustain their daily consumption.

As for the summoned Undead, whether high-level or low-level, the basic purpose of summoning them is for battle.

If they win the battle, they can absorb the souls of their enemies, which not only satisfies the needs of their daily activities but accumulating more can even lead to their evolution.

And if the battle is lost, there’s no need to say more; they’re dead anyway, so consumption no longer matters.

The reason why Dong Tianyu was so clear about this was not because he came to such conclusions after observing those Undead Creatures that had been included in the Cave.

In the beginning, when the undead creatures were killing each other, Zachary thought they were doing it to devour their own kind for evolution, so he just kept catching new undead creatures and putting them into the Cave to see if he could directly breed higher-level undead.

However, with the end of the Undead Disaster, it became difficult for Zachary to continue capturing new undead to send into the Cave, so he began to consciously limit the internal conflicts among the undead within.

When initially restricted by Zachary, the undead tried to rebel, but as time went on, even the lowest-level skeletons started to fall into a deep sleep voluntarily.

At first, Zachary thought these undead creatures had become smarter, choosing to enter a dormant state because they couldn’t break free from his constraints.

But as the lower-level skeletons in the Cave started dying off one after another, Zachary gradually discovered the problem and realized that the undead could actually starve to death.

It was only after understanding this that Zachary occasionally sent live livestock and poultry into the separate Realm of the Undead within the Cave.

These animals would quickly die upon entering the Realm of the Undead, and the death energy they released on death satisfied the basic needs of the slumbering undead, effectively halting the continual deaths within the realm.

The condition for generating death energy, or the power of Ten Thousand Spirits, is quite simple: any creatures that die, whether it be their souls or their bodies, will turn into death energy after a period of time following their death.

Normal creatures exposed to death energy will gradually deteriorate and die, while their souls will become tougher but will slowly transform into undead creatures.

Though the conditions for generating death energy are quite straightforward, the methods for its dispersal are even simpler: under normal circumstances, as long as the sun rises, death energy will gradually disperse, unless it’s in places of extreme yin where the sun never shines, otherwise, death energy won’t accumulate.

Despite the terrifying effects of death energy, if normal creatures inhale it, they just need to spend more time in the sun and the death energy absorbed into their bodies will naturally disperse.

Seeing this, some smart folks want to exploit a loophole by first inhaling death energy to make their souls tougher and then sunbathing to disperse the death energy within them.

It’s a good idea, but they don’t realize that the efficiency of death energy in fortifying souls is far less than its efficiency in transforming them into undead creatures.

If exploiting such a loophole were so easy, cultivators would have used it not just for their own cultivation, but also to train their descendants.

Understanding the role of death energy for the undead creatures, one should realize why the Undead Necromancers or Wizard Wraiths, despite having skeletons as cheap labor, don’t utilize them for mining or other basic work to earn money but instead are eager to wage war.

Although the money earned might exceed the cost of buying livestock and poultry, from using skeletons for collection, to transporting and selling them, and then buying animals with the proceeds—

Leaving aside the fluctuations in product prices throughout the process, even if everything goes smoothly, it’s also time-consuming and labor-intensive. Although it might not result in a loss, the cost-effectiveness is definitely not high.

Compared to this troublesome and less cost-effective method, the Undead Necromancers and Wizard Wraiths prefer to instigate wars.

No matter whether they enter the battle themselves or not, as long as it’s called a war, naturally, there would be a significant number of dead on both sides.

No matter which side has the upper hand in the battle, the undead definitely don’t lose out, after all, no enemy can prevent the Undead Necromancers or Wizard Wraiths from capturing souls and seizing spirits during the fight.

After the battle ends, the death energy permeating the battlefield is exactly what their subordinate undead need.

It is because of such low investment and high return activities that the undead are so eager to instigate wars wherever they may be.

After all, once the battle starts, no matter who wins or loses, the undead don’t usually come out worse off.