Demon Lord's Reincarnation

Kir was the first to take action and with a speed that went beyond the speed of sound. Kir created a sonic boom by simply moving and was ready to slash at Kretos using his claws. Kretos summoned pillars of ice to block Kir's path, but Kir was able to slice them apart.

As Kir sliced through the numerous pillars of ice with his claws, a spear suddenly appeared from beyond the wall of ice. Kir was quick enough to knock it over, but he noticed that Kretos was no longer in front of him. With Kir's sense of smell, he should be able to smell Kretos's scent, but to his surprise, he couldn't get a whiff of his scent at all. Kretos had disappeared, it was at that moment Kir remembered Kretos's original profession, assassin.

Kir stood in the middle of the field of weapons when he noticed something weird happening to his shadow. Kir quickly moved his body when a halberd alongside Kretos appeared from his shadow. Kir could barely dodge this surprise attack and was nicked in the cheeks. 

As Kir was about to counterattack, Kretos plunged the halberd down used it as a springboard, and took a nearby sword to attack Kir first. Kir once again evaded the attack. Once he missed Kretos threw the sword he was holding at Kir, and then picked up some daggers on the ground and threw those as well. 

While Kir was distracted with the thrown sword and daggers, Kretos started running around the field of weapons and throwing everything he could pick up.

Kretos then charged forward alongside the thrown weapons. Kir could not dodge the incoming attacks at such a tight space so instead of dodging he started deflecting the incoming weapons. Kir could've destroyed all the weapons with a beam of mana, but he couldn't use that technique too much. He had already used it a lot at the beginning of the battle, which drained a significant portion of his mana.

Using this as an opening, Kretos was then able to get up close to the speedy Kir and slashed at the demon lord, who countered with a piercing strike using his claws. Both Kretos and Kir didn't dodge the attacks and simply hardened their defense. Kretos's downward slash didn't reach Kir's bones and only tore a bit of Kir's flesh. 

Kir's piercing claws, on the other hand, were also unable to pierce deep enough which only gave Kretos a minor flesh wound. Both of their wounds healed up almost instantly. The two who witnessed what happened started smiling and laughing happily. It would seem that only a truly fatal wound could damage the other party, or if their mana supply runs out. 

The two once again began attacking and attacking without any care in the world. Kir used his advantage in speed to get around, while Kretos used the diversity of the many weapons he had all over the place to change his form of attacks. 

...

The battle between the two grew fiercer and fiercer after every passing second. Every time Kretos lost a bunch of weapons he would simply summon more from his shadow. The whole armory in Demon Empress Nimune's palace could supply a hundred thousand men, and that was how many weapons Kretos had in store. 

He kept on tossing and slashing about but no matter how much damage he or the demon lord received both of them wouldn't go down. Their wounds would heal almost instantly due to their excessive mana supplies and characterstics as demons. By how it looks, it would seem that both of their mana supplies were near equal. 

If Kretos had faced Kir at the beginning of his journey he would've died, even facing Kir's normal form at the time would've spelled death. But as Kretos continued to fight he grew stronger and stronger, until he finally reached this stage he was currently in. Yet even with his power increasing, which was happening even now as he was battling, Kir was still able to keep up with him.

...

While Kir was dodging the thrown weapons, Kretos was gathering mana into a ball. This was the spell Demon Empress Nimune used against him, and he was going to unleash a stronger version of it at Kir. 

Being bombarded by weapons on all sides, Kir wasn't that worried as his speed when in his Wolf form was truly fast. Kir was able to dodge and parry all the incoming weapons. He was even able to catch and toss some of them back to Kretos. On the other hand, Kretos was also dodging the incoming attacks while gathering mana and even tossing some more weapons towards Kir. 

It was at this very moment, Kir's sensitive nose which could smell even mana itself caught a whiff of the mana Kretos was gathering. Knowing what's to come Kir wasn't planning to dodge it and instead, he shouted at Kretos. 

"Come on boy show me what you've got!" 

"Heh, so you've figured it out already... Since you already know about it no sense in hiding it." Kretos lifted both of his hands upward and a ball of pure mana appeared. At first, it was just a tiny ball, no larger than an orange, but then it grew and grew that it eventually became bigger than Kretos himself. 

Kir could've intercepted Kretos while he was gathering mana, but he wanted to face this attack head-on. For the first time in centuries, he could feel his blood burning with excitement. Kir and Kretos looked at each other their respective grins would've scared other demons. Yet to them looking at their opponent's grin just made them feel more excited.

...

The ball of mana grew and grew, when Kretos felt like he had depleted a huge chunk of his mana he knew that he was ready to throw it at Kir. Of course, Kretos also knew that if this ball of mana were to fall, it would destroy everything around it. So Kretos was also readying himself to hide in his shadow the moment he felt that the situation was unsafe. He didn't really like doing that but that was his only choice at the moment since he wasn't strong enough. 

Kir saw the ball of mana had grown to an unbelievable size. It was mana that came from Kretos himself, and it was a horrifying amount. Simply standing in front of it would have made a weaker demon perish. Kir then planted his feet onto the ground his hands extended forward. He was ready for whatever Kretos tosses at him. 

"Are you ready Demon Lord!" 

"Show me the extent of your power!" 

With that as the signal, Kretos threw the ball of pure mana at Kir. The ball of destructive mana was unleashed and everything in its path was destroyed be it the weapons stuck on the ground or even the very ground itself. Kir faced the ball of mana with no fear or hesitation. There was only joy and excitement on his face. 

Upon releasing the ball of mana Kretos felt extremely tired as he had used a large portion of his mana. Yet he did not fall as he too had a look of excitement and joy in his face. He wanted to see if Kir was able to handle the incoming ball of death. 

...

Upon contact with the ball of mana, Kir could feel his hands being torn apart. He then gathered a large portion of his mana into his hands and was trying his hardest to push the ball of mana away. Kir started growling as he tightly grabbed the enormous ball of mana. The ball of mana had pushed Kir a few meters backward but it was finally slowing down. 

Kir forced all of his muscles to their very limit until he was finally able to stop the ball of mana from pushing him back. During this time Kretos could've attacked Kir, but that was not the kind of victory he wanted. The other reason for not attacking was because Kir didn't attack when Kretos was gathering mana to form the ball of death. 

...

Kir who had finally stopped the ball of mana was now trying to shove it away. As he was going beyond his very limits he could taste the blood on his mouth, he could feel his very bones slowly breaking. 

"THIS ISN'T ENOUGH TO BRING ME DOWN!" 

Kir was finally able to redirect the ball of mana upward into the sky. The large ball of mana kept on flying beyond the horizon destroying the clouds in its path. 

Once he was done Kir started panting heavily as his wounds were now healing slower than before. His body had gone beyond his very limits.

"That was an amazing spell Kretos." 

"What's even more amazing is how you were able to withstand it and redirect it." 

The two once again looked at each other and laughed. Despite both of them being exhausted they continued to radiate an aura of wanting to do battle. 

"I'm glad that I met you in the end." Kir who still had some fight left in him could already guess the outcome of the battle. Kretos was continuing to improve while he was slowly losing stamina. They might look to be on equal footing but that might not last for long. 

"It has been quite lonely here at the top... I'm glad that you can keep this old man company." Kir chuckled as he said those words. 

"Don't worry old man, I will keep you company until you no longer feel so lonely."

"That's good to hear!" The two once again began their battle that would last for days.