A few hours and many missing limbs from both sides piled up on the ground later, Polix started to get nervous. This boy, who wasn't even at the middle tier of the 6th stage was somehow outpacing him, and had regeneration that rivaled his own. For every hand or foot that Polix managed to sever, he was losing two to three whole limbs.
Not to mention that immediately after being severed from Kayn's body, his hands would immediately reattach back in place due to the black tentacle like things. Kayn's feet would regrow though oddly, so he was currently barefoot, his boots lost somewhere in the gore below.
However, Polix was in a much worse state. His armor was torn to shreds, both of his arms were void of any type of clothing and his legs matched. He had holes and gashes in his plate armor and even his crotch had been blown off with the lightning blade at one point.
His body parts had created such a large pile below them that it was starting to look like a small hill by this point. Finally, his nerves began to get to him. He was sweating and could feel that his mana reserves were below 50% now, which was unthinkable for him. Unless he cast spells for months on end, he wouldn't use that much mana. However, somehow within only a few hours, he had already used over 50% of his mana.
"Dammit! Dammit! Dammit!" Polix yelled as his envy of Kayn grew stronger, but Kayn remained nonchalant as he only increased the aura of Kindness around his body when he felt Envy trying to push in again.
Polix looked at Kayn and noticed that despite losing his limbs on occasion, his head and torso were perfectly unscathed aside from the still repairing clothing on his chest from the earlier sneak attack. How was this boy, who was not even a hundredth of his age able to lead the flow of battle so well?
Polix decided to swap tactics and swiftly retreated, while Kayn surprisingly let him get some distance without pursuing him. Polix was breathing heavily once he stopped and turned to stare at Kayn who was calmly looking at him like some sort of ant. Kayn even deactivated the Elemental Sword Domain and was just floating in the air without moving, waiting for Polix's next move.
"WHY! WHY AM I NOT AS GOOD AS YOU! WHAT YOU HAVE SHOULD BE MINE!!" Polix screamed at the topic of his lungs as his envy became even stronger. He spread his mana throughout the ruined city and began lifting entire buildings of stone and earth before tossing them at Kayn one after the other.
This move caused a reaction in Kayn as he truly didn't expect the emperor to try and throw the entire city at him! He tried to take over control of the giant pieces of rubble and earth from Polix's mana, but with Envy's interference, he couldn't. Unfortunately, there was little he could do at this point besides create barriers around himself.
Little to Kayn's knowledge, but this spell was one of Polix's signature spells, Earth Maiden's Tomb, just on a much, much larger scale than he usually cast it. The earth and rubble surrounded Kayn on all sides despite his attempts to break through and soon he was completely enclosed within a space of earth that was rapidly losing an interior cavity.
Kayn was pushing out with all of his mana on his barrier spells to hold them in place, but then the true terror of the emperor's spell came into play. Millions of pencil thin earth spikes erupted from the interior walls of the cavity, not a single space left unfilled.
All of these spikes slammed into Kayn's barriers at the same time. The majority were blocked and destroyed upon impact, but once the barriers' protection was broken, a small number of the total spikes got through and pierced his body completely. A small amount may not seem like much, but a small percentage of a million was still several hundred spikes.
At the last minute, Kayn gave up all defense of his body in order to focus all of his efforts towards defending his Demonic Dragon Heart. He had to sacrifice a majority of his mana to use small precise circular void spheres to absorb the spikes that would have pierced his heart otherwise.
Soon after the spikes, a crushing pressure descended, which flatted the entire tomb's interior, and smashed Kayn straight into the ground, the earthen spikes embedded within his body either going in further or breaking off inside.
Polix had used 30% of his entire mana pool with that spell rotation. Using an entire city that was miles wide as materials for his spell was mana intensive, but the results were worth it. He could sense the force pushing against his Sin fading with every second that passed as he stood in the sky intently gazing at the spot where Kayn should have fallen.
"Damn bastard, how could he put up such a fight against me?! I should be the strongest in this world! It's my destiny to rule this world, yet such an insignificant ant pushed me to such lengths. Oh well, I squashed him before he could become too big of a problem, and now I'll have his body to experiment with, though I'll need new research assistants…"
As Polix became lost in thought thinking the fight was already done, Kayn's body was slowing repairing itself and expelling anything that didn't belong. He was unconscious from having his brain pierced through in every direction, but as soon as it grew back, his anger for getting caught in such a trap reigned supreme. He was too confident in himself and acting unlike how he would usually approach a fight, with caution.
It was time to stop messing around. Polix needed to be brought to his knees and Kayn wasn't going to hold back anymore. Even if he had to deplete his mana reserves, he would end this as quickly as possible.
He could sense that Polix had roughly 20% of his mana left now. If Kayn went all out from the start, he wasn't sure about his victory if the man still had mana, but now that Kayn was close to exhausting him, he only needed to finish off what little remained before he could end this once and for all. It was time to use the void fusion elements.
Storm clouds began gathering overheard, which Polix found odd but he still brushed it off as he sat down atop the rubble to rest his tired body for a bit. He felt an odd disturbance in the mana above him though and just as he looked up, a massive black lightning bolt fell straight at him. He barely managed to move out of the way, but his arm was still caught up in the blast.
He looked at his left shoulder and noticed a lingering black mana where his arm was once attached. Pushing mana into his phoenix heart, he began the regeneration process. Only this time it was much slower, taking a few seconds to complete rather than being instantaneous.
Polix looked up in fear as he heard the sound of rubble moving. He watched as Kayn appeared from where he should have taken his last breath, covered in a white-golden glow. His armor and appearance were in tatters, but every moment that passed caused his limbs to fix themselves from their bent angles and his hole-riddled flesh.
Kayn's eyes opened to reveal black orbs with golden hues in his sockets, staring straight at Polix. Before Polix could even react, and with a speed he hadn't used before, Kayn appeared in front of him, spearing his hand through Polix's body.
When he removed it, there was a still beating heart within his grasp. Before Polix could say anything, black flames engulfed the heart and it was soon gone from existence, not even ash remained.
"No! You can't take what is rightfully mine! I started from nothing when everything in this world should have belonged to me! You can't take it!"
"Your envy borders on greed you know?"
Polix became enraged after his phoenix heart was taken and destroyed just like that. Despite all of the protections in front of it, somehow Kayn had bypassed them all to destroy the heart he worked for years to integrate into his body and mana system!
Like a kid throwing a tantrum, Polix cast spell after spell at Kayn. Meanwhile, Kayn simply engulfed himself in a barrier of Extinction Flames, which destroyed every little thing that passed into them before they could reach him. A few minutes into Polix's barrage, Kayn started shooting small bolts of Extinction Lightning at his limbs, annihilating the emperor's body one piece at a time.
It didn't take long, 30 minutes at most before the spells stopped flying Kayn's way and Polix was missing the majority of all of his limbs. Only stumps remained of the man, keeping himself supported upright by earth spells. Kayn dispelled his barrier and began to approach Polix who was crying with snot and blood running down his face.
Even more embarrassingly, Polix's mana ran out at that instance, so he was sprawled on the ground before Kayn without any support anymore. "Please! Please don't kill me! I beg you! We can work together and make this world a better place! You can rule and I will be your ever loyal servant!"
Kayn's left hand reached out to lift Polix into the air by his hair. Once they were face to face, Kayn slapped him hard on his face.
"That was for killing my sister."
*SLAP*
"That was for killing my mother."
*SLAP*
"That was for killing my father."
*SLAP*
"That was for forcing my little sister to grow up without any parents and separating me from her during her childhood."
Each slap was progressively more violent. Polix thought his head was going to be slapped straight off, but to his surprise it wasn't a slap that hit him next. Kayn coated his hand in wind mana and whatever Sword Aura he could manage with his amateur technique and just like before, he pierced his hand into Polix's torso pulling something out.
"And this is for me." Kayn said as he looked at the orange and brown mana core in his grasp that was surprisingly showing traces of the other elements.
Polix looked at his mana core in Kayn's grip in horror. If true despair hadn't reached his mind yet, it did now.
"NOOOOOOOOO-" Polix screamed, but alas his cry was cut short as Kayn engulfed his entire body in the strongest Extinction Flames that he could manage with what little mana he had left. Kayn reached into the flames and grabbed a single ring hidden in Polix's belt before it was destroyed by the flames.
Soon, the once tyrannical and monstrous Emperor of the Carnet Empire, Polix Carnet, was nothing more than a terrible memory in the minds of those who had lived through the last few years of his reign.
A black ghostly wisp exited the Extinction Flames as they burned away the last of Emperor Polix's body and Kayn caught it with his hand covered in the aura of Kindness. Without hesitation he brought the wisp to his forehead where it then seeped into his soul.
Having over-exerted his mana and body, Kayn wobbled a bit before plopping down onto the ground and leaning back.
"It's finally over…I can finally find Lara and Kinzie again." Though the thought of Kinzie brought complicated emotions to his heart, but he still desired to see her regardless of how things turned out.
The fight was much shorter than he imagined, but he truly didn't expect that both of them would have to spend so much mana right off the bat with the way their battle took place. Rather than being a battle of strength of spell, it was a battle of attrition to see who could last longer, and fortunately Kayn won.
He hadn't brought out the void fusion elements at the start for two main reasons, they had been slapped away by more powerful mages before and he didn't want to waste his mana if that was going to happen before Polix was weakened.
Second, they still cost too much mana. It wasn't anywhere near as bad as 5% each spell cast like it used to be, but it was more than what Kayn was willing to spend once he learned the battle was going to come down to who ran out of mana and the ability to regenerate faster.
Using his wings as support, Kayn stood up and flew out of the area without any mana, back to his former home, which was now nothing more than a crater in the ground. He set up the Wanderer's Villa and entered inside before quickly activating all of the formations it offered.
He bathed, took a short nap, and then ate the ice cream he saved from Earth as a celebration of his victory, even popping a bottle of champagne to drink.
Once he was finished with his celebrations, he made his way to the mana gathering room of the Villa which he had upgraded over the last couple of years after seeing the room inside the Palatine Palace.
He sat down as he pulled out Emperor Polix's mana core, staring at it and wondering how much stronger he'll become. Before that though, he had one other issue to take care of.
Kayn focused his consciousness into his mind space, which was technically just his soul. He found Envy and guided it to its proper place, a harmonic ring formed between it and Kindness. Relief washed over his mind and soul and the insanity that he was holding at bay with Wrath was no longer pushing on him.
Thus, for the first time in over two years, Kayn deactivated the portion of Wrath he kept active at all times. His eyes reverted to their beautiful crimson color with golden accents, and his aura wasn't filled with bloodlust any longer. Wrath itself went right back into place with Patience and formed a harmonic ring, just as Envy and Kindness did.
Emotions of guilt and remorse immediately flood into Kayn's mind, but now wasn't the time to dwell on what had already been done. He can rehabilitate himself after he finds Lara. For now, he will absorb everything Emperor Polix's core can provide him with before following the desire that's been in his heart ever since being sent to Earth.