Over the past year, although the main task was to build a city, Roy would occasionally send people to explore underground.

Just as everyone had estimated, because of the existence of demon worms, the underground world here had been dug so much that it was riddled with holes. Countless tunnels and caves interconnected deep underground, forming a network that was more complicated than an ant nest.

In Roy’s words, it was a massive underground maze.

Previously, he had used Demon Eyes to explore underground. But unexpectedly, even he became lost. There was no light in the dark underground world at all, so he lost his sense of direction after exploring a few places and did not know where he was. He had no choice but to send people to explore.

He had sent out a total of four waves of low-rank demons. But unfortunately, these low-rank demons were either eaten by demon worms or other underground creatures, or they were totally lost in the maze and could not find the way back. In the end, he could only summon them back. The efficiency of the entire exploration plan was shockingly low, and so far, only about a kilometer underground had been explored.

After the underground exploration suffered successive setbacks, Roy could only put this matter aside for the time being. But after Frostfire City was most or less completed a while ago, this matter was once again on the agenda.

It could not be helped. After a year of exploration, Roy found that the surface of this fragment world was too barren. The extremely cold climate had caused no creatures to survive on the surface, and he had not even seen any frost-element monsters. Occasionally, some mineral veins were found, but all of them were poor, and there were traces that they had been excavated a long time ago.

This made Roy wonder if this fragment world had other masters before…

If he wanted to excavate these mineral veins, thick layers of ice would have to be dug open, but these newly dug ice layers would soon freeze again. It was extremely troublesome, and the mining efficiency was very low. In the end, Roy gave up on them and turned his eyes underground.

The good news was that he had the colossal demon worm, Big Black. Although this mutated demon worm could not speak, it had high intelligence, and some simple communication could be done with it.

During this period of time, Benia had been communicating with Big Black and training it. Her goal was at least to get Big Black to understand her requests and guide her in the underground world. Now that Benia had asked Julia to inform him, it meant that there was progress. Roy and Julia left the demon palace and flew toward the crater.

On the ground at the foot of the volcano, an enormous cave had been dug. By the side of the cave, Benia was already waiting. Not far behind her was the… obese Big Black.

And Fat Tiger, this silly guy, was lying beside Big Black, and from time to time, he would get up and reach out his claws to touch Big Black, as though he wanted Big Black to play with him. But after being reprimanded by Benia twice, he lay down unhappily.

Roy found it slightly unbearable to look at this scene. After landing, he tried his best not to look at Fat Tiger’s aggrieved eyes and asked Benia, “Are we going to go down personally?” “Yes!” Benia raised her wings and floated over to hug Roy’s arm. “Now that Big Black basically understands my command, I think we can go down and take a look.”

“Okay, let’s go!” Roy nodded. “Julia, stay here. I’ll leave a Demon Eye with you. If anything happens, I’ll contact you. You can look after Fat Tiger.”

Julia nodded. “Okay.”

Benia placed her right hand in her mouth and whistled at Big Black. Big Black’s immense body slowly bent down, and Roy and Benia jumped onto its head. After sitting down, Benia patted its hard skin, and it headed into the enormous cave.

Roy’s vision suddenly darkened as he entered the underground on Big Black. Big Black had dug out this cave, so it looked gigantic. Even though he was sitting on Big Black’s head, it was still tens of centimeters away from the top of the cave. Big Black carried Roy and Benia and headed downward diagonally. At this moment, Roy’s darkvision began to play its role, and the dark underground gradually became visible.

Along the way, Roy saw a large number of forks flash past. Needless to say, demon worms had dug out these underground tunnels. He did not know where they led. Moreover, magma was still flowing in some of the tunnels, as though the demon worms had dug through the volcano wall and caused magma to flow out.

“The passage we’re in should be one of the tunnels that Big Black dug before!” Benia said to Roy. “These demon worms have a sharp sense of smell. They will leave their own scents in the tunnels they dug themselves to help them determine their paths. I originally wanted Big Black to bring us to find the mineral vein that caused it to mutate, but this description was too complicated for it to understand, so I asked it to bring us to the place where it goes most often!”

“Yeah, if Big Black mutated by devouring ores, the vein is definitely where it goes most often!” Roy nodded.

Big Black was not too fast. Roy could feel that it was not going straight down all the way and instead often made turns. It seemed that it had basically dug tunnels randomly in the past. Now that it wanted to go back again, it could only go along these tunnels since the tunnels dug by the other demon worms were too small for it.

Even so, Roy and Benia went down by about two kilometers in a short time. Roy was not sure how much it was exactly, but he roughly estimated it through the temperature changes.

Since there was a volcano, it meant that the veins of the volcano connected to the magma layer underground. Generally speaking, magma formed in the depths of the crust or in the upper mantle. This distance was about thirty to fifty kilometers from the surface. There was a large amount of high-temperature liquid here, which was magma. If the magma layer connected to the volcanic channel, then under the pressure of the tectonic plates, it would transmit bit by bit to the upper part of the volcano. When the pressure of the tectonic plates was too great, the volcano would erupt, which was why seismic activity often accompanied volcanic activity.

Now that Roy and Benia were going down, the temperature they felt did not decrease but instead became hotter and hotter. This heat came from the heat emitted by the magma layer. It was extremely stuffy in this tunnel that did not have much ventilation.

As Big Black continued to go deeper, the temperature in the air had already risen to about 100°C. This temperature had already exceeded the temperature of the Abyss, and even Benia felt slightly uncomfortable, so Roy put an ice armor on her to help her resist the heat.

“How far is this guy going?” Benia was surprised. “Is the mineral vein it foraged from not in the magma layer? If that’s the case, it’ll be difficult for us to mine even if there are ores!”

Before Roy could speak, he suddenly saw an object flash past in a passage. He was shocked and quickly said, “Stop! Stop! Benia, get Big Black to stop!”

Benia did not know what was going on and quickly kicked Big Black a few times. Big Black received the signal, so it stopped rushing down and slowly stopped in the tunnel.

Roy did not wait for it to stop before spreading his wings and flying back along the tunnel. Benia followed behind him. Then she saw him suddenly stop at a fork and look in it in surprise.

“What’s wrong?” Benia caught up to Roy. He did not answer and pointed at the fork for her to see.

With this glance, Benia was extremely surprised because she saw something obviously artificial in the fork! There was a broken wall, or rather, a part of a building. This thing was embedded in the rock wall of the tunnel, revealing only a portion. If not for Roy’s sharp eyes, they would have missed it.

After flying over, Roy pulled this thing out of the rock wall and carefully observed this fragment.

“It’s a demon creation!” Benia said with certainty. “This style is very familiar. It should be… part of some statue!”

“In other words, there were really demons in this fragment world before!” Roy said. “It should be a demon lord, but he was different from us and put his lair underground!”

In fact, Roy had suspected this from the beginning. This fragment world was very suitable for frost demons to settle down in. It did not make sense that no other frost demons had found this fragment world over the years. But he had been here for more than a year, and he had never seen any demon come out and say that he had invaded their territory.

Recalling what Demon Lord Anivia had said before, that someone was hunting frost demons, Roy thought that even if other frost demon lords had occupied this fragment world before, they would have probably been killed.

But when he saw the fragment of this demon creation, he realized that he had guessed completely wrong. It was not a frost demon who had occupied this fragment world. On the contrary, this former master had placed their lair in the very hot underground world!

“Is it a demon lord of some insect-type demon?” Benia clearly thought of this and guessed. “In my impression, only insect-type demons like to place their lairs underground.”

“Won’t we know after looking around?” Roy raised the statue fragment in his hand. “But even if it’s really an insect-type demon lord, I think it’s most likely gone. This thing looks very ancient. Who knows how many years ago it was…”