"True enough." Yuki nodded.

"Anyway, I am going to make a route for us first," said Kai while listening to the footsteps around their position.

"Oh. We need to fight in an efficient way after all unless you want us to fail despite having so much advantage." Yuki grinned.

"I absolutely don't want to imagine what she will do to me later." Kai shook his head furiously.

"I will leave you first." Yuki smiled before stretching her hands to him, asking for the bottle in his hand.

Kai already finished drinking, so he handed the bottle to her. "Thank you."

Seeing Yuki walk away, Kai closed his eyes and listened to his surroundings. No one could escape from his ears, especially the last four thousand magical beasts around the area.

They were currently in the north area of the Underground Nest containing ten thousand magical beasts. The middle and south areas had around twenty-five thousand and fifty thousand magical beasts respectively.

The complexity of the tunnels which were connecting with each other, the movement of the magical beasts, and the operation of humans were calculated in his mind. Each of them became a factor for Kai to create a good path where they could continuously move to a new path where they found monsters.

The five-minute break turned into a ten-minute break as Kai finally broke his immersion and opened his eyes. The group that had been waiting for him since a few minutes ago stared at him, wondering if he had gotten the answer.

"Let's go." Kai smiled at them and pointed out the tunnel on their back. "I will guide all of you."

All of them took out their weapons instantly and nodded.

The group continued sweeping the entire north area of the nest. Most of the area consisted of thirty to sixty magical beasts inside, where they created a small lair for them. Kai used these spots to decide where he would go.

They conquered another five of these and rounded their kill to nine hundred monsters. Kai still watched the marbles this place had. From how they created a complicated like this, where he could go up and down or even left and right.

The tunnel itself was dark, making him wonder how they could move around in this darkness. Earthworms aside, he didn't know whether ants originally had something that could be used underground. He ended up shaking the thought off because it wouldn't matter to him whether they originally had it or got when they evolved. His mission was still the same… which was to kill them.

Just as Kai predicted, their killing rate was slowly decreasing because of the lack of monsters. There were some magical beasts that managed to get skipped by the soldiers, and all of them had a quite amount of distance.

Although Kai instructed they needed to patrol the area around until six hours were up, the soldiers began getting lazy when the magical beasts became too scarce inside the northern area. They started walking instead and looked around while relaxing.

Kai couldn't care less about them as they had admirably fulfilled their jobs. Out of ten thousand magical beasts, only around two hundred remained, and usually, the students would handle these two hundred magical beasts that might pass the front line.

Unfortunately, there was no student that had a job like that, except Kai and his group.

Kai could pinpoint their locations because of his hearing. He asked Yuki to split the group to destroy all of these magical beasts. Of course, the map had been marked by Kai to let her see where the magical beasts were.

Yuki had no problem and brought her five-person team to do some cleaning, and the same applied to Kai's group. Even Sanae rarely agreed with a chore like this. She said it was better than sorry, and the group finally moved out.

On the way, they met a few teams that were patrolling around. Rather than having them lazy like this, Kai instructed them to kill magical beasts in a certain location, making his job easier. He asked them to inform the next group they met to take down the locations he pinpointed. Yuki did the same thing according to Kai's instruction, and they got around one hundred people joining the fight before long.

They destroyed the magical beasts' lairs and finished the entire northern area. For the reward of their efforts, Kai informed them that their mission actually had finished. In other words, they had two hours of free time and could go to the surface to rest earlier. He told them not to spread the news for other soldiers and let them suffer because they didn't do anything in particular.

This one hundred people had no intention to inform them either. They had earned this rest with their hard work, so unless they were like best friends or family, they rather let them suffer a little bit. Nonetheless, they wouldn't meet another magical beast after this, so they were not cruel to the other soldiers.

After getting to the surface, Yuki and Kai reported to the main headquarters where Ria and Nathan stayed.

"Phase three is completed."

"Good work." Nathan nodded. "Let us send the support team so we can move up our schedule."

"Don't." Kai shook his head. "It's alright not to move up the schedule and let the soldiers work first. They won't know anyway."

"Don't be like that. They are still soldiers, you know." Nathan shook his head. He could picture how the soldiers turned lazy after completing ninety percent of their objective. However, it was better for them to rest because they can take the next missions more seriously."

"Our schedule was made by also considering the amount of time they needed to sleep. With these three phases alone, we almost used a whole day. We would require another five days to finish this entire base, so it would be better to have the soldiers rest early," said Nathan, objecting to Kai's decision.

"I don't mean to punish them a little. Looking at the fourth phase, where the support set up a small base in the Underground Nest, it will surely take time. Nonetheless, the support team wouldn't go so deep and reach every team inside the nest. If we send them now and inform a few that meet the support, they will think it's unfair." Kai shrugged.

Nathan fell into silence and looked down.

Kai used this silence to add another thing. "Besides, the foundation is the thing we need to be careful of."

"I know that already." Nathan let out a long sigh. "Fine. It's not like we lost much in either case. Killing ten thousand magical beasts and setting up a base on the first day is already quite an achievement."

"That's right. You need to be thankful to my student for this. Without his hearing ability, you won't have a good grasp on the Underground Nest and how complicated the nest was. If you charge blindly, I'm afraid you will need a few months." Ria Ross decided to join the conversation. "Besides, it's already a huge achievement to end a raid mission in a month, let alone a week. If I remember correctly, Michelle has used a few months in the last raid mission."

"Kh!" When Ria said that, he had no words. As she said, the last raid mission was close to the graduation exam for the third year and continued for two months after the new curriculum started. Had Michelle not participated in this mission, she would already get Kai's message.

Kai learned this on his date with Michelle. He asked about what kind of mission that would take her that long. Although Michelle didn't say anything about the Raid Mission at that time, it was easy for Kai to speculate this was the only mission that would take too much time.

"I'm thankful for his hearing as well." Yuki stepped forward and said with a smile. "If we don't have his ears, he wouldn't be able to clean the beasts this early and pass your requirement."

Ria snorted, looking very proud of her student before staring at Nathan again. "Anyway, the fourth phase is only to have the support team inside and create small bases inside with the fifth phase to have the Vanguard advance once more. We have separated the nest into five areas: North, East, Middle, West, and South. Using this guidance, we will be able to finish them in five to six days.

"However, the hardest part of this mission will be conquering the West, Middle, and South areas. Not only do we need to be careful with those three areas, but we also need to watch out for the magical beasts from the southern part of this nest. It's better to use this opportunity to tell them this was a different style of the front line as we need to constantly watch out from magical beasts."

After the long explanation from Ria, Nathan had no choice other than agreeing to her claim. "Alright. We will continue according to our schedule."

Kai looked at Ria with a smile, watching how she murder Nathan with her words. He walked toward her and bowed. "Teacher, I have finished my mission."

"Yeah. That little girl said it earlier. Well done." Ria smiled.

Kai stared at her for a few seconds before shaking his head, like he was telling her something. No one knew other than her about this gesture. Ria nodded her head with a gentle smile.

"Then, I'm going to rest a bit. There is still half a day before the next operation."

"Sure."

Kai bowed his head once more to her and nodded to Yuki and Nathan before leaving the tent.