Princess Moon's eyes glowed more than ever and she started to chant something that was a forbidden technique that could only be used by the members of the royal family of the Xiao kingdom.
She whispered "Golden Sparrow" and a giant sparrow formed above Princess Moon's head inside the Hell cage.
The golden sparrow's aura was terrifying and its strength was almost at the peak of the Sky Realm cultivator but the destructive power it possessed was far beyond that.
The golden sparrow opened its mouth and a golden ball started to form and after it completely formed, the golden sparrow launched it against the Hell cage from the inside. From this attack, the entire Hell cage shook violently and some little cracks also could be seen but the Hell cage didn't break.
The barrier was only present outside the Hell Cage, so it couldn't prevent attacks from inside the Hell Cage. However, surprisingly, the Hell cage itself was very tough and couldn't be broken so easily.
That golden ball could easily injure, if not kill, a normal peak Sky Realm cultivator. However, the Hell cage withstood it with only some minor cracks.
When Kadin saw and felt the threat coming from the golden sparrow's strike against his Hell cage, he muttered "Not good".
He who was previously carefree, now feels it is time to get really serious because if the Hell cage breaks he will eventually die. So he started to burn his royal blood power to heal and strengthen the Hell cage. As a result, those small cracks that had appeared on the Hell cage healed quickly and the toughness of the Hell kingdom also increased a lot.
The golden sparrow had just started and made more golden balls, attacking continuously on the Hell cage. For this continuous attack, Princess Moon was also paying the price, which was that she was burning her royal blood power just like Kadin, who was burning his royal blood power to maintain the Hell cage.
The forbidden techniques of the royal families work like this. They could be strengthened as much as their users want if they provide sufficient royal blood power. The only drawback was that the royal blood power could not be used infinitely. If royal blood power is completely exhausted inside the body of a royal family member of any clan, it cannot be replenished.
For it to be replenished, it is necessary to have some royal blood power remain inside the body of a royal member. Otherwise, that person will never be able to use the power of the royal blood again, which is also the reason why royal families of any kingdom don't use their forbidden techniques easily. Using them requires their royal blood power, and if by any chance they exhaust their royal blood power completely, they would never be able to use their forbidden techniques again in their lifetime.
On the other side, after so many failures in breaking the barrier, Kallu realized his current giant robot's condition was not good and it couldn't break the barrier protecting outside of the Hell cage, so he retreated his giant robot.
Kallu then looked at Kadin, who was focusing on maintaining the Hell cage. So he took out his cloak and wore it, which made him invisible. He started to silently approach Kadin.
When he was only three feet away from Kadin and confirmed that he was not paying any attention to his surroundings, Kallu quickly took out a sword and slashed towards Kadin's back. But surprisingly, a barrier appeared around Kadin, which protected Kadin from getting killed by Kallu's sword.
Kallu quickly stepped back when he saw his surprise attack was blocked by the barrier and created some distance between them. Then he started to observe the barrier around Kadin.
That barrier was the same barrier that was protecting the Hell cage. It had also appeared around Kadin, so it was clear that the barrier was not only protecting the Hell cage from outside attacks but also protecting Kadin, who had cast it.
Kadin looked back and sneered "Weak people like you have the courage to sneak attack me, but how unfortunate - even though you got a successful sneak attack on me, it was all in vain because you can't penetrate this barrier. Not even a strong peak Sky Realm cultivator can break this barrier, let alone you."
Kallu didn't get offended by Kadin's words and asked, "Even a strong peak Sky Realm cultivator can't break it? So it must place some kind of burden on you, isn't it? Because I can't believe you can use your family's forbidden technique and also cast such a strong barrier to protect it."
Kadin smiled a little even though he was giving it all to maintain the Hell cage and said, "You are a smart one. I really can't use both of these things at the same time on my own. But what if I have an artifact that can create a strong barrier after absorbing the strength of cultivators?"
Kallu's face got saddened when he heard this and he asked, "How many people did you sacrifice to be able to use this type of artifact?"
Kadin replied with an indifferent face, "Not much - just 10,000 cultivators, in which 100 people were Sky Realm cultivators, although the majority of them were in the early stages of the Sky Realm, and some were in the mid-stage."