Lu Heng put away the sonar equipment and issued commands to the contract beasts beside him with his mind.
"This is an opportunity for you to train together, but be careful of the zombies inside. There might even be some zombie animals."
In this wild environment, there were bound to be infected zombie animals.
Those animals were smaller and harder to detect. If they were injured by them, they would surely be infected.
Lu Heng really wanted to contact Wuming City to see if an antibody against the zombie virus had been developed.
Glancing at the sky, Lu Heng suddenly had the idea of restoring communication in the apocalypse.
There were too many things to do.
Lu Heng had the Fire Phoenix and the Golden Eagle act as vanguards. The Golden Eagle could boost the Fire Phoenix's flames, allowing them to spray fire further and cover a wider area.
"Fly as high as possible, but just in case, don't fly too close to the cave ceiling."
Lu Heng was also worried that there might be some zombie animals hanging from the cave ceiling, such as vampire bats.
Those bats might have been infected after biting zombies.
Several Fire Phoenixes lined up, with the Golden Eagle standing behind them.
Then, the Fire Phoenix and the Golden Eagle took off simultaneously. In the blink of an eye, they flew into the cave, leaving only fiery red afterimages.
The moment the Fire Phoenixes entered the cave, they gathered the energy within their bodies, opened their beaks, and spewed fierce flames forward.
The temperature in the cold and damp cave instantly rose. The Golden Eagle behind the Fire Phoenix also flapped its wings, continuously releasing gusts of wind to fuel the flames.
For a time, the flames were like a wall of fire, pouring down from above, illuminating the cave with a bright red glow.
The flames spewed at the cave entrance did not burn any zombies, but they did dry out the cave.
However, as they ventured deeper, sharp screams of zombies echoed from within.
The zombies, encountering the high temperature, were like fiery orbs, struggling incessantly in the cave.
Even some zombies with fire abilities could not withstand the high temperature when subjected to flames much higher than their own level, and their bodies began to burn.
For a moment, from the cave entrance, the roars of the zombies inside and the crackling sound of burning fat could be heard.
An unpleasant odor wafted out from within.
Animals had keen senses of smell. Lu Heng had the contract beasts waiting at the cave entrance retreat a bit further. They only needed to surround the cave entrance.
The Fire Phoenix and the Golden Eagle carrying out the mission inside were not significantly affected.
The Golden Eagle flapped its wings, not only fueling the flames but also regulating the air around the Fire Phoenix and itself, isolating the smell of burning from below.
Soon, the sounds of zombies inside gradually diminished, and the Fire Phoenixes and the Golden Eagle flew to the end of the cave.
They turned around, preparing to return. After spraying flames all the way, the cave was now filled with the sight of burning objects, and the oxygen was becoming scarce.
Just as they all turned around, the air wall behind the Golden Eagle was hit by something flying up from below.
The object probably didn't expect to hit an invisible wall. It then fell rapidly downwards, plunging into the burning zombies below and being quickly consumed by the flames.
But before the Golden Eagle and the others could fly far, more objects crashed into them, desperately lunging at the Golden Eagle and the others, trying to get close.
"Hmph, what dares to crash into me like this."
The Golden Eagle looked back with disdain. Under the reflection of the firelight, the objects hitting the air wall behind it were clearly visible.
They were indeed some bats.
Seeing the continuous stream of bats, the Golden Eagle added more wind blades to its wind wall.
Instantly, as the crashing bats hit the wind wall, they were cut into several pieces by the wind blades, their shattered bodies falling towards the flames below.
"Master, there are quite a few bats inside. They've come out following us."
Although the Golden Eagle had killed many bats, on its way back, it noticed that the bats were no longer foolishly crashing into its wind wall, but were simply following behind.
Even as they were about to exit the cave, the bats behind them showed no signs of turning back, and their numbers were not small.
Inside the cave, they couldn't surpass the wind wall it created. However, once they left the semi-enclosed cave, the bats would no longer be blocked by the wind wall. Perhaps they would attack Lu Heng and the others after exiting.
Therefore, when it saw that the bats were no longer crashing into the wind wall, it reported the situation to Lu Heng.
"Mm, be careful. We are all on alert here."
Then Lu Heng instructed the contract beasts waiting outside: "Be careful, the ones coming out with the Fire Phoenixes might be zombie bats. Don't get injured."
Upon hearing this, the contract beasts became even more focused, all staring intently in the direction of the cave.
Lu Heng glanced behind himself and his contract beasts. At this moment, everyone was focused on the situation at the cave entrance. They couldn't let the zombies outside launch a surprise attack.
Then, Lu Heng waved his hand, and a sturdy high wall instantly rose behind him, blocking potential dangers from behind them.
The surrounding grass was also quite dense. As Lu Heng erected the high wall, he pulled all the plants under their feet into the ground.
In an instant, they stood in an unobstructed open space, waiting for the zombies inside.
Soon, the Fire Phoenixes and the others reappeared in Lu Heng's sight, but the swarm of bats following them also appeared at the cave entrance.
Without the obstruction of the Golden Eagle's wind wall, the bats immediately began to pounce on the animals outside as soon as they emerged.
As they got closer, Lu Heng knocked down a bat and pulled it in front of him to examine it.
Indeed, they were zombie bats.
"Fire Phoenixes, change direction and continue to suppress the bats with fire. Golden Eagle..."
Lu Heng continuously issued commands to the contract beasts with his mind. With their efforts, the emerging zombie bats were immediately suppressed.
Bat corpses littered the ground.
Lu Heng's contract animals were experienced in killing zombies. Those with single-target attacks aimed only for the zombies' brains.
Those with area-of-effect abilities attacked indiscriminately. Most of the zombie bats that flew out of the cave were eliminated by them.
The cave entrance was also piled with many bat corpses.
It seemed that these bats were guided by higher-level zombies inside.
Seeing that the bats outside were suppressed, Lu Heng then summoned Lin Xue from his spatial storage.
"See how many levels the zombies inside are."
The moment Lin Xue appeared, the zombie bats that were still flying out instantly turned around and flew back into the cave.
Their levels were very low, and they relied entirely on numbers to attack.
But upon sensing higher-level zombies, they became fearful and retreated instinctively.
Even with the intense heat inside, it could not stop them from fleeing from this more dangerous existence.