Demon Lord's Reincarnation

The moment Alfred finished saying what he said, he teleported farther away while chanting. Ren started chanting as well while dashing forward following Alfred. Unfortunately for Alfred, he couldn't teleport multiple times in succession, while Ren could catch up with the sheer speed of his movement. 

When Ren caught up with Alfred he was about to slash down, but Alfred was finally able to finish his chant first. "[Ice Castle]" a giant fortress of ice was formed in the middle of the battlefield. This fortress was emitting an extreme level of frost, making anyone or anything that touches it transform into an ice sculpture. 

Ren who saw the spell used by Alfred smiled that vicious smile of his, he knew that Alfred would use such a spell. Based on their last encounter with the Elder Lich Alfred, it was easy to guess that his preferred magic spells revolved around ice. 

So Ren had chanted a spell that he was familiar with in his past life, now that he had the appropriate amount of mana he could use some of his old spells. "[Pitch black]" A huge ball of darkness engulfed the ice castle making it disappear. 

Alfred was surprised by the spell Ren used but was still able to evade on time. As Alfred was about to land on the ground, he heard Ren activate another spell, "[Shadow Bind]" Alfred was then caught by a shadow that appeared underneath his legs. 

Ren was about ready to swing his scythe at the helpless Alfred, but then as he sliced at Alfred's body it disappeared, it turned out to be nothing more than an illusion spell. Then numerous bone lances surrounded him, but Ren countered with, "[Black hole]"  a darkness spell that draws-in mid-tier spells that was within a few meters away from it into a void neutralizing the spell used. Though the size was smaller than the actual size of the original spell, it was still enough to devour the bone lances. 

After dealing with the bone lances, Ren was then able to locate Alfred and once again charged at him. Alfred couldn't understand what was happening, even if Ren was able to enhance his mana this battle shouldn't be going this way. 

No matter what kind of genius Ren was, he was still a sixteen-year-old human child. His knowledge about spells shouldn't be this good, and he also shouldn't be able to to use such complex spells. The scene before him was unimaginable. The last time he fought Ren, it felt like Ren was more of a warrior than a mage, but now it seems to be the opposite. Not only that, Ren was actually using original spells and from the darkness attribute no less.

It was at that moment Alfred felt something familiar. This style of fighting was something he has seen before, even the spells though original felt a bit familiar. Still, he had no time to think as Ren was happily slicing at him. 

"[Summon Doom Knight]" a magic circle appeared in front of Ren and from that magic circle a knight clad in pure black appeared. This was the strongest being that Alfred could summon, it was even stronger than the undead dragons. That summoning spell had taken a lot of mana from Alfred, so he needed to unsummon the two undead dragons. He had no time to be bothered with Valdel and Lara since he felt that the person in front of him was more dangerous than he initially thought. 

Ren seeing the Doom knight in front of him, made him smile widely from ear to ear. Ren was aware of how strong this thing was. During the age of chaos at the height of his power, his elite force led by one of his Demon generals that later on betrayed him consisted of these Doom knights. An undead dragon was a dead dragon with barely any mana left from when it was alive. A doom knight, on the other hand, was something that was clad in mana. As long as it had mana it supposedly would never fall, which made them perfect vanguards. 

Ren couldn't help but laugh as he saw one of the things he used to rip apart like toys. He knew of dozens of ways to destroy this thing, even in his current weak form. When Ren was about to face the Doom knight, Valdel and Lara appeared beside him. 

"Val, Lara! Stand back! I don't need your help." Hearing what Ren said Lara immediately backed off, but Valdel stayed. "Val I told you to leave! Against somebody of this level, you'll be nothing more than a burden." Ren didn't even bother looking at Valdel as he said this. Valdel was trembling in anger at himself as he retreated.

"That pride of yours will be your downfall," Alfred spoke as he started gathering mana while chanting. He just needed the Doom Knight to stall Ren for a few minutes so he can use his strongest spell. 

The Doom Knight stood in front of Ren menacingly which made Ren laugh even louder. "Hahaha! My downfall with this much? Against a toy like this? You're hilarious!" Ren then coated the death scythe with Spirit Aura and Mana, this was an extremely watered-down version of Leo's ultimate move, but it was still strong enough. Ren casually swung the scythe at the Doom knight and it was erased from existence. 

If Alfred was still alive he would've shown a paled expression the moment he saw Ren killing his strongest summon with one move. Yet as a lich, he wasn't affected by such emotions, still, he knew that there was no longer any chance for him to win. No matter what angle he looked at the two options left was to die again or try to flee.

As he waited for Ren to finish him off, Ren simply stood there waiting. "What are you doing? Go on finish your spell." 

"What do you mean, aren't you going to eliminate me?" 

"I will, just after you used that spell of yours. Last time I was forced to retreat due to various reasons, but this time I want to take on your strongest spell, then beat you. Only in that way will I be able to say I truly won." 

Normally Alfred would think that Ren was joking, but the moment the Elder Lich saw the crazed expression on Ren's face he knew that this human wasn't kidding. It was also at that very moment the face of a being he seen long ago, back when he was still human surfaced in his mind and overlapped with Ren's face. Though Ren and this person didn't look remotely alike, the facial expression he was showing was exactly the same. 

A thought then came to Alfred but he immediately denied it. It wasn't possible, that being was the strongest being he has ever seen. Even though Ren was strong he paled in comparison to that person, in front of that person Ren was nothing more than an ant. So why did they feel so alike? Alfred then remembered the spells Ren used, those were some of the spells that person used against thousands of human warriors. The scale of the spells was different but there was no denying that they were the same spells. 

"Demon Lord Kretos..." Alfred whispered the name and Ren was surprised to hear it coming from Alfred. 

"Heh, how do you know that name?" Ren asked a bit curious, in which Alfred responded by pointing his bony fingers at Ren. "You're Demon Lord Kretos." As an undead Alfred no longer felt emotions even the joy he has shown was nothing more than an act, but now a feeling he thought he would never feel again surfaced from within him. He was feeling fear, he remembered that bone-chilling fear he had when he first laid eyes on the demon lord. It has been a few thousand years since he existed, he has seen the rise and fall of numerous kingdoms and Empires, but he still felt this extreme fear in front of this person. 

"Oh, interesting you were actually able to recognize me. I wonder who you were in my past life... Well, it doesn't matter, just use your strongest spell and be done with it. If you don't use it, then don't blame me for dying again without giving everything you got." upon learning Alfred's connection to him in his past life, Ren looked a bit interested at first, but then that interest faded as fast as it came.