A thought flashed through Quan Xiaoyu’s mind, and a crystal-clear crystal core appeared in the palm of his hand.
The crystal core was surrounded by a rainbow of colors, its hues even purer than when it had first been removed from the infant zombie’s brain.
That’s right. It was the very same crystal core Quan Xiaoyu had taken from the brain of the psychic infant zombie two months ago.
Since Quan Xiaoyu himself was not a psychic-type ability user, he had never paid much attention to this crystal core.
Besides, Quan Xiaoyu knew that although zombie crystal cores could help human ability users increase their ability levels—especially crystal cores from rare ability-type zombies, which had very significant effects when absorbed by an ability user of the same type—using crystal cores had one fatal drawback.
Crystal cores were taken from the brains of zombies and carried mutated viruses. They could only be used safely after being purified.
If someone used one without purifying it first, there was a chance the ability user would mutate into a zombie. Although mutation was not guaranteed, no one would willingly risk their life just to conduct an experiment, right?
In addition, purified, attribute-type crystal cores also had a certain chance of awakening abilities in ordinary people. However, these attribute-type zombie crystal cores had to be obtained from ability-type zombies, so they were relatively rare.
As for ordinary zombies, their crystal cores had no color. After purification, they could be used by ability users of any type, replenishing their abilities and providing a certain boost.
In his previous life, by the third year of the apocalypse, there were only two methods that had been made public—or, rather, that were widely known among ability users.
The first was purification through a second-level healing-type ability user.
The second involved mutated plants, which had appeared in large numbers after the apocalypse. The fruit of one particular mutated plant could purify the virus on a crystal core. As long as the fruit was swallowed before using the crystal core, it could then be safely absorbed.
However, healing-type ability users were rare to begin with. It was not until a year after the apocalypse that the first healing-type ability users began reaching level two. At the same time, most healing-type ability users were controlled by large organizations or powerful factions, so ordinary ability users could not even get access to them.
Moreover, there was a limit to the number of crystal cores they could purify each day.
Trying to purify crystal cores through this method was simply too difficult.
Then there were the fruits of mutated plants. These plants had no fixed appearance, and their forms varied tremendously. At the same time, there were many poisonous plants that looked similar. It was difficult for humans to distinguish them based on ordinary knowledge of color, smell, or appearance, so this method carried a certain degree of risk.
Even so, during the apocalypse in his previous life, most ability users still took the risk and chose this method, because it was much easier to obtain than a healing-type ability user.
Of course, there might have been a third method, or even a fourth, but those resources were still controlled by government forces or other major factions. They were beyond what someone at Quan Xiaoyu’s level could know about.
After obtaining the infant zombie’s crystal core, Quan Xiaoyu had decided to try it on a whim and thrown it into the small river in his space.
After all, that little river had once purified the virus in his own body.
After throwing it in, he had almost completely forgotten about it.
Over the past two months, after Li Nan’s ability broke through to level two, the four of them had actually been quietly using ordinary zombie crystal cores to level up, with Li Nan responsible for purifying them. As a result, all four of them had reached the late stage of level two.
Originally, Chu Tian had been the fastest to reach the late stage, but for some unknown reason, he had suddenly encountered a bottleneck. He remained stuck there until the others caught up, yet he still failed to break through.
That forgotten infant zombie crystal core had simply remained submerged at the bottom of the river. Even during Chu Tian’s bottleneck period, Quan Xiaoyu had never remembered it.
But now, with the situation so urgent, he suddenly thought of it.
At this moment, the crystal core lay in Quan Xiaoyu’s palm, dazzling with multicolored light and crystal clear.
It had never been purified by Li Nan, but it had been soaking at the bottom of the river for a very long time.
Quan Xiaoyu regretted never having paid attention to it, to the point that he had completely forgotten about it. Now that Li Nan was not by his side, he could only take the risk and try.
He could not just stand by and watch Chu Tian suffer like this, could he?
He could only gamble that the water from his space’s river had purified this crystal core just as it had purified him.
Quan Xiaoyu opened Chu Tian’s left hand, placed the crystal core into his palm, and then helped him close his fingers around it.
“Chu Tian, can you hear me? Absorb it! Just like we normally do, absorb it!” Quan Xiaoyu pressed his lips close to Chu Tian’s ear and shouted, hoping that Chu Tian could still hear his voice.
The four of them had absorbed crystal cores plenty of times over the past two months. Quan Xiaoyu had taught them how, and by now they were all thoroughly familiar with the process.
What Quan Xiaoyu feared most at this moment was that Chu Tian could not hear him.
Fortunately, the thing he feared did not happen.
After hearing him speak, Chu Tian’s body twitched slightly. His left hand tightened into a fist, and before long, multicolored light began to swirl around it.
Quan Xiaoyu let out a breath of relief.
This meant Chu Tian had begun absorbing the crystal core.
However, his relief did not last long.
Absorbing the crystal core was only the beginning. What mattered most was what would happen afterward.
Would he mutate?
Would he be able to defeat the opponent attacking Chu Tian?
Would it help him break through his bottleneck?
Everything was unknown.
At this moment, Chu Tian was trapped in a painful struggle.
His opponent’s level was clearly one level higher than his. At the same time, the opponent’s attacks contained fragments of memories. Those fragments were all gray, saturated with negative energy—disappointment and hatred toward humanity.
Chu Tian was being forced to receive this information, and it was extremely painful.
But after Quan Xiaoyu placed the crystal core into his palm, that pain was relieved.
In fact, Chu Tian’s consciousness was still relatively clear. He could still sense what Quan Xiaoyu was doing.
Therefore, the moment the crystal core entered his hand, Chu Tian, who knew exactly what the crystal core could do, immediately began absorbing it frantically.
Until the crystal core completely disappeared from his palm.
To his surprise, the energy contained within this crystal core was incredibly pure and immense. It was completely different from any crystal core he had absorbed before.
The energy was extremely pure and perfectly compatible with the psychic power inside his body. He did not even need to spend any effort organizing or regulating the energy. It flowed directly from his palm into his brain, then instantly spread throughout his entire body.
Chu Tian’s mind rapidly cleared.
The influx of new power caused his energy to suddenly surpass the energy attacking him.
Chu Tian did not let the opportunity slip away. He gathered his strength and launched a counterattack.
A few seconds later, a sharp howl rang out from among the mass of zombies outside the building.
The strand of psychic power Chu Tian had sent out to investigate also returned to his mind after making a circuit outside.
At this moment, Chu Tian opened his eyes.
“You’re okay?” Quan Xiaoyu stared intently at him, not even daring to blink.
Chu Tian immediately smiled at him and unconsciously reached out to pat Quan Xiaoyu’s face.
“Don’t worry. I’m fine. I broke through the bottleneck.”
His white teeth showed as he smiled. That usually calm smile now carried an inexplicable warmth.
Inappropriately, Quan Xiaoyu’s face flushed slightly.
He turned his head away and stood up almost as if fleeing, jumping over to the window. Trying to cover up his embarrassment, he said, “I… I’ll check the situation outside.”
Chu Tian let out a soft laugh and did not seem to mind at all.
He quickly stood up, not forgetting to brush the dust clinging to his body off.
It was only then that Quan Xiaoyu discovered that the zombies outside had all stopped attacking the building at exactly the same time.
Quan Xiaoyu was astonished.
The zombies’ movements were perfectly synchronized, almost like a well-trained army.
It was astonishing. It completely went against the nature of zombies.
Unless they were being controlled.
Zombies without intelligence could only submit to the desires of their bodies and attack humans endlessly. They did not feel fear and did not think. At least, zombies below level five basically did not.
Moreover, the zombies had already taken over the first floor. Quite a few level-two zombies had even climbed up the walls. Now that they had suddenly stopped moving, the other ability users were able to knock them down one by one.
What could make them give up the flesh that was already within arm’s reach?
Quan Xiaoyu looked at Chu Tian, hoping to get an answer from him.
Sure enough, Chu Tian did not disappoint him.
“The one who attacked me was a psychic-type ability zombie. It was hiding among the zombies outside. My counterattack just now seems to have injured it. The huge horde of zombies outside seems to be under its control. It’s really powerful.” He sighed.
An ability-type zombie?
And a psychic-type one at that.
This was definitely not good news.
“Can you beat it?” Quan Xiaoyu asked seriously.
Chu Tian smiled bitterly and shook his head.
“Just now, I relied on the energy from the crystal core to break through my bottleneck in one burst. The opponent was caught off guard, which was why I managed to injure it. Its level is clearly higher than mine. I’ve only just reached level three. If it recovers and attacks again…”
He shook his head.
“The consequences are hard to predict.”
The moment he finished speaking, they were pleasantly surprised to discover that the zombies had actually begun retreating as a group.
The other ability users inside the building gradually stopped attacking as well. Faint cheers could be heard from the floors above.
It seemed that, whether mentally or physically, the other two groups of ability users had also reached their limits.