Pride felt disbelief at his opponent's regeneration. The darkness allowed him to know the minute changes that were happening around his opponent right now. He was able to feel his body create bones, flesh, and nerves in such a short time that it almost felt like he was being created again by God.
If his perception had not been strong enough, it would have been like his opponent had healed in an instant. But feeling each and every step it took to do it actually made him more fearful than he would have been if he had seen it in an instant.
Immediately, he tried to take back his spear to run. Even though he could not escape the seal without breaking it, the wisest among the seven deadly sins was feeling such an extreme level of fear that he wanted to run as far away as possible from what was causing it. But it was too late.
Karna's hold on both Pride's arm and spear had only tightened instead of weakening in the last few moments. And with an even wider grin, Karna repeated his words.
"Didn't I tell you just now, you should have gone for the head?" He brought his arm up while channelling the absolute maximum amount of death energy he could muster right now. Even though his physical body had healed completely, he could feel that he wouldn't be able to maintain the demon slayer form for long.
Pride was trying his utmost best to escape. He even took out a knife from somewhere and tried to cut off his arm that was being held down by Karna, but it was far too late. And Karna never made mistakes like letting the villain escape during a monologue. He was charging up death energy while talking to him.
"Noooooooooooooooooooo!!!!!!!!!!" A scream echoed through the entire cavern, which was now left with a single human who had eliminated every other living being that had ever been present within it.
Karna took a deep breath as the mission-complete messages appeared in the system. But instead of giving a reward, the system had decided to store the energy acquired from changing an important point in time to use again later.
Karna was fine with it, as he knew he had to do something to make sure his body did not shut down when he went back into normal form. But thankfully, the method was right in front of him as well.
The moment he killed Pride, the darkness around him had increased in both quantity and quality by a hell of a lot compared to the others. It seemed like completely wiping out an entire species from this world had its effects on what they left behind.
He immediately started absorbing the entire darkness through his mouth. He had become so efficient at it that, even though the amount was greater than anything he had ever consumed before, he was able to do it within a short amount of time.
As soon as he completely absorbed the entire darkness, he felt the heaviness in his body reduce by a lot. And seeing that there was no corrosive darkness left around him, he released the death demon slayer form and slightly stumbled forward but corrected himself quickly.
'Hmm, seems like it did take a toll on me. But there is still enough strength left in my body to escape by teleportation if needed,' Karna thought as he inspected the sealed space after all the darkness within it was removed.
'Whoa, that's a lot,' Karna muttered in his mind as he clearly saw what the space was made out of entirely. It was made up of redstone, with the entire place etched with runes that even he was unable to recognize. Karna even used his mind palace to check whether he had seen it somewhere before, but was disappointed to find that he hadn't.
But the most shocking part was the enormous number of runes etched in this place. From the system-given information, Karna knew that the last Fate Breaker was ambushed by the demons while he was weak, and not the other way around. So basically, while being weak and being ambushed, he managed to create such a sophisticated seal spanning a few kilometers.
Even if Karna and Freed were combined into a single person, the chances of creating a seal like this were very low, and even if they were successful, the time required for it would take months or even a whole year.
This made Karna realize the horrifying reality of the beings that had existed a thousand years ago. He had thought Acnologia and the other dragons were the most dangerous species in the world. But for a wizard about to die to be capable of such a massive spell made him realize that he was lucky he had the system when he came to the world.
For the demons to corner such a man, they would have needed many times the power displayed in front of him today. If the system had not been there to warn him and the demons had escaped to spread and recover their powers, Karna shivered at the thought.
He then came to the last room to find the demon's seal that made sure no demons escaped from this place while allowing humans to pass through it easily. He was able to see that it was flickering. It seemed like it had drained energy from the darkness released by the demons. But since they were dead, there was nothing left to hold this entire sealing space. So the chances of it breaking down were very high, and if unlucky, it would trap Karna within it.
As Karna turned around to leave, a system window appeared in front of him.
[Host has completed the required mission. Would the host like to use a bit of energy acquired by the system to transport himself to Edolas?
The host is currently in a place where the space is continuously fluctuating. It will be easier to transfer the host while he is in this place rather than outside, plus the expenditure of magic will also be low.
Would you like to accept?]
The system asked, to which Karna agreed as he vanished along with the sealing space that destroyed itself.
A/N- hope you like it.