One thing made Krune puzzled, though. He then looked at Iem and asked through a Divine Sense Message.

"Without sentience, those underground demon beasts can only move on instinct. In that case, how come they joined together for this assault? Not only that, but they are also separated in ranks, with the strongest ones being on the back. Also, what relation does it have with the protection barrier?"

Iem pondered a bit before saying.

"I don't know about how they can organize like this. Perhaps it's just instinct built after thousands of years of beast hordes. They came to slowly understand that this is the best way to advance after so many tries."

Krune had to admit that Iem's words had some credibility.

Iem then continued.

"As for the city's protection disappearance, I have an idea. Most likely, it's not that the demon beasts come when it is about to disappear. Instead, the barrier disappears after the beast horde comes. Look at the number of demon beasts outside. If all of that attacks the barrier together, it will sooner or later crumble. Suppose this protection formation is destroyed in that way. In that case, it will be very complicated to repair in a resourceless place like this Underground City. That being said, it is better to turn it off so that it can be used during the years that the beast hordes don't appear."

Krune agreed with Iem.

"I see... That makes sense. In that case, whoever is controlling the barrier, and turning it off is most likely in the Godly Tower. It seems like we have one more reason to go there later."

As Krune and Iem talked, the first waves arrived at the city's wall. The first group of Soul Forging Realm cultivator engaged the Demon Beasts promptly. The higher level cultivators didn't step forward since they had to save their energies for the stronger demon beasts. However, Krune didn't like to see all those deaths, so he decided to give a hand from far away.

Of course, Krune was talking about both sides. So he summoned arcs of lightning that struck the demon beasts, causing severe injuries and making them faint. Of course, it wasn't Luvile's Purple Tribulation Lightning. Krune's attack didn't kill any of them but ended their time in the siege. Obviously, the cultivators close to where Krune was attacking rejoiced with that.

Elder Huan looked at Krune and gave him a warning.

"Save your energy for the time the 15 to 20 meters Rarin Worms come. If you tire yourself now, you will increase the chances of dying when your strength becomes necessary. It might look like you are saving our companions, but once you die, the stronger beasts that you could have fought against will cause even greater damage than what you prevented here."

Krune smiled at Elder Huan before answering.

"That's why I'm not using much energy. These attacks I'm sending out are not enough to surpass my rate of recovery. I can continue like this for an entire month, and I won't get tired."

Elder Huan was taken aback. He then looked at the lightning flying at the demon beasts in the distance and narrowed his eyes. Krune's attacks were really strong and seemed to use a lot of energy, so it was hard to believe Krune.

"Are you sure you won't run out of energy?"

Krune nodded with a confident expression.

"I'm really good at absorbing Godly Energy, elder Huan has no need to worry."

Huan could only nod in the end. Still, he paid close attention to Krune. If he sees that Krune is starting to faltering, he will immediately stop him. Suddenly, a fireball's shower began to strike another side of the wave. This time, the one who was doing it was Iem. Obviously, those fireballs were just normal ones. Iem didn't use the Devil Flame God's power.

"You too?"

Iem laughed out loud before saying.

"Elder saw that how I finished the test. Don't worry, I'm also using very little energy, so my recovery rate can keep with it."

Iem began to help Krune with the attacks, further spreading the area of damage. The only difference was that Iem wasn't trying to not kill the demon beasts. If they survived, so be it. If not, that's okay with him too. Krune didn't say anything since his method would still leave a higher number of survivors than leaving it up to the weak cultivators at the front.

Of course, even though Krune and Iem were causing massive scale damage to the beast horde, it didn't change the situation as a whole considering the number of enemies. It could be said that the Soul Forging Realm cultivators close to Krune and Iem won the lottery.

As time passed, Elder Huan got more and more impressed with Krune and Iem. Those two seemed to have an unlimited supply of Godly Energy. It really seemed that their recovery rate surpassed the amount of Godly Energy they used.

At dumb as the beasts might be, they still wouldn't charge blindly into a barrage of lightning and fireballs. So after some time, they began to shift their positions, trying to avoid the places where Krune and Iem were acting.

That obviously made the surroundings receive more demon beasts than they would initially. Immediately, the cultivators defending those positions paled at that sight. Too bad, though. Those demon beasts were acting on instinct, rage, and fear only. All Krune and Iem had to do were to change the direction of their barrage of lightning and fireballs. Not only that, because the demon beasts got more packed, the efficiency of their attacks increased even more.

The sea of Soul Forging Realm cultivators at the front cheered at that sight. The other cultivators close to Krune and Iem couldn't help but look at them with admiration. The city might be chaotic, but everyone united when the beast hordes came attacking. Anyone who could prevent a lot of deaths would definitely gain everyone's respect.

Elder Huan had been prying into Krune and Iem's condition all this time. So far, neither of them showed the least bit of exhaustion. If anything, Iem would yawn now and then as if he was bored. In the end, Elder Huan couldn't help but nod, satisfied.

'Those kids are the future of our Cinna City.'

The first wave lasted for over four hours. Finally, the bigger demon beasts on the back began to move as well. Obviously, it was time for the Void Breaking Realm cultivators to step forward. The Soul Forging Realm one didn't retreat, though. Instead, they stayed there to give support to the Void breaking Realm ones fighting. Besides, the weaker demon beasts haven't stopped coming, so they had to deal with those as well. The assault at the city now was a mix of Soul Forging and Void Breaking Realm level demon beasts.

Krune and Iem didn't mind that. The only difference was that they had to focus their attacks in smaller areas since the enemies were stronger. However, the demon beasts were just like the cultivators. The stronger they are, the shorter their numbers. So Krune and Iem's attacks were still as effective in the situation as a whole as before.

Just like that, an entire day passed in a flash. Well, because they are underground, no one could see the sun. Still, everyone had their ways to check the time. In the end, the beasts sieging the city began to retreat. That also concluded the first day of the assault, which went better than expected. No Demon Beasts at the Divine Path Realm level or higher joined this time, though.

As one can expect, countless deaths were inflicted on both sides. However, because the demon beasts don't have intelligence, the numbers on their side were much higher. The Nascent God cultivators who didn't participate in the fight soon came forward to clean the battlefield. One must not forget that the meat from those Demon Beasts was what most of them will eat during th next years.

Not too surprising, Krune and Iem's position suffered the least amount of casualties. All the low-level cultivators there couldn't help but feel delighted to have been dispatched to this place. Elder Huan even patted their shoulders with a smile, praising them for their efforts.

The city seemed to be really used with the beast horde. In just six hours, all the demon beasts' corpses that could be used were pulled into the city. As for the rest, they were quickly disposed of as well, leaving the battlefield in the best conditions for the cultivators to fight the next day.

The injured ones were brought back into the city, while those who were tired retreated as well. From inside the town, a new batch of Soul Forging and Void Breaking Realm came out to take the place of those who fought the first day. Through this rotation system, the city could last even longer than if it deployed everyone at once.

Krune was curious about one thing, though.

"Elder Huan. You said that the Divine Path Realm and the above cultivators should save their energies for the stronger demon beasts. But during the first day, no demon beast of that level appeared. Wouldn't it have been better if the Divine Path Realm and the above ones helped then? After all, they could use this resting time to recover their energy to their peak."

Elder Huan bitterly smiled as he shook his head.

"The reason is simple. We don't know when the higher-level demon beasts will attack. They might attack the very first day or only in the last. Some times, there isn't any resting time like this one you are seeing today. The siege might continue for several days straight if the demon beasts feel like it. That being said, we simply can't risk it."

Krune nodded. He had thought about this possibility but wanted to confirm first. Elder Huan then patted his shoulder once more before saying.

"Rest well, the next attack might happen at any moment."