Genius Mage in a Cultivation World

"Good job, everyone!" Castor shouted, praising his soldiers. 

"URA!" The entire unit chanted in response, allowing their bloodlust to fade away through that shout. 

'That was... weird,' Layn thought, focusing his eyes on the escaping enemies rather than joining in the victory celebration. 'Aren't we supposed to be in the depths of Slavian lands? Where did those people come from then? Bandits?' Layn's mind spurred into action, producing more and more possible scenarios that would explain the strange situation. 

"But the fight isn't over yet," Castor announced, turning his head towards the bloodied ground where the battle took place. "Everyone, find the wounded and cater to their wounds. Separate our dead from those barbarians! This fight isn't over for as long as every wounded is taken care of!" Castor shouted his order, instantly dismissing the entire unit.

'What the hell?' Layn's eyes widened when he heard such order. 'I know that taking care of the wounded is a basic thing to do, but right after the enemy retreated?' Layn moved his eyes in the direction where the enemy ran off to. 

'They are too slow,' Layn thought when watching the retreating unit Castor's soldiers just clashed with. 'Are they running, or is this actually an organized retreat?' He asked himself, unwilling to tear his eyes away from that sight. 

"Come on! I can see someone still breathing!" A sudden shout near Layn forced him to look around. And just like the archmage internally expected, the entire broke down. 

There was nothing left of their initial cohesiveness. No one kept the formation. Following Castor's order, all the men jumped into action as one. 

"Castor!" Layn shouted, hoping to get the man's attention. 

Sadly, the man either didn't hear the shout, decided to ignore it, or was simply too busy to respond to it. 

Layn looked in the direction where the enemies ran off to once again, only to see the distance between them and Castor's unit... It didn't change at all ever since he last looked towards them.

'An illusion?' the archmage guessed, unable to keep himself calm anymore. 'If that's right,' Layn tightened his fists before jumping off his horse, 'then I don't really have much choice.' 

Even in his current state, Layn was far from being powerless. While his fight with the Overlord of Origin forced him to use all the means he had on hand, it didn't mean Layn used all the tricks he knew off. 

Not because he was holding back in that fight, but simply because there was no way for him to use some of the other methods. 

And right now, standing in the middle of the bloodied grounds, there was more than ample amount of a single resource that Layn was capable of turning into magic energy. The mana that was likely to come useful given the deception Slavian's enemies used to make them lower their guard. 

"Layn, did you call for me?" Castor appeared on Layn's side when the archmage already entered the state of full focus. With his entire attention oriented at invoking one of the academy-forbidden spells, he could no longer hear anything at all.

"Layn, are you okay?" Castor continued to pester, unaware of the insane focus that Layn had right now. 

"RISE!" Layn suddenly shouted before biting on his lips. 

The cut wounds opened up all over his body. Rather than pouring out, the blood gushed out of his wounds. 

But it didn't fall to the ground. Rather than that, it started to orbit the archmage, forming dense circles of red all around him.

This situation instantly drew the attention of the entire unit. 

"They are coming," Layn spoke softly as more and more blood converged around him. At some point, his wounds healed all by themselves. But, with the source of the blood now cut, the same blood that sunk to the ground before started to gravitate towards Layn's external bloodflow. 

"What the hell are you doing?!" Castor shouted, showing hostility to Layn for the very first time since they met. He even went as far as placing his hand on the handle of his weapon. 

"You are a great tactician," Layn spoke suddenly, completely ignoring Castor's question. "But you are a shit strategist," Layn shook his head before moving his eyes back in the direction where he expected the enemy to attack from. 

"What the hell are you talking about?" Castor reached the edge of his patience. He pulled out his knife, clearly regretting letting Layn borrow his sword. 

"Here, you will need it," Layn threw the sword towards the commander without even batting an eye. "Also, get your people in the formation. They are coming," he added after a short moment. 

"What the hell are you..." Castor asked as he turned his eyes in the same direction Layn was focused on for a while already. "..." once his eyes looked in the direction Layn wanted him to look, Castor no longer had it in himself to keep bashing at the archmage. 

"If not for me, you guys would fall for it," Layn spoke softly, not holding a grudge against the way Castor treated him a moment ago. "I hope you will keep that in mind later on," he added before releasing all the air in his lungs. 

Then, Layn breathed in as much air as he could before closing his eyes and shouting, "CONVERGE!" 

All the blood that surrounded him in circles broke its shape before hitting Layn's hand. At first, it appeared as if this blood attempted to cut through Layn's skin, returning to his inner flow of blood. But as more and more red liquid converged on his hand, it started to take the shape of a slightly curved, one-sided sword.

"Argh..." Layn fell on one knee when the forbidden spell concluded. Even though most of the blood used for the blood saber technique came from the battlefield, the backlash of using it was still considerable. 

"Are you okay?" Castor asked after he gave his orders to the people. His eyes glanced towards the bloody weapon in Layn's hand, yet the man himself didn't dare to ask about it. 

"Do I look like I'm all right?" Layn moaned in response. 

In order to invoke a blood weapon, one had to sacrifice his own blood to establish a core of the weapon and find out a source of a lot more human blood to make up for the blade proper. 

But that wasn't the end of it. The usage of blood weapon spells was forbidden by the very academy that Layn graduated from. It came from the fact that such a weapon had to be constantly maintained with more and more blood. 

The good side of using this spell was that one could regenerate his mana by consuming the blood of humans or evolved monsters. Yet, the fact that even a small cut on the enemy's body would result in the entirety of his blood getting drained made the civilized people of the future quite wary of the spell.

The bad part about using that spell was the burden it placed on the caster. Invoked too quickly before the fight, and one would sap his physical strenght before the clash. Invoked too late and one would end up without a weapon once the fighting would start. 

"They are coming," Layn spoke up in a weak voice. "I need to kill at least one," he added after a moment when the burden of the blood saber in his hand was getting too big for him to handle. 

"I see," Castor replied, most likely putting some kind of expression on his face, something that Layn was too tired to move his eyes to notice. "Here, you can kill him," he added after a moment, pulling in one of the injured.

"Is he one of your soldiers?" Layn asked, too tired from the blood loss to actually use his eyes. In his current state, he could only ask.

"No, it's one of those fuckers. I can bet he thought he was..." Castor was in the middle of explaining when Layn swung his arm. In a single attack, he cut the wounded man's head off.

"AAAAH!" The moan of pleasure escaped from Layn's mouth. 'This feeling,' Layn's eyes widened when a surge of energy entered his aura. 'It's addictive...' Layn swayed as if he was drunk. Once he regained his stability, his eyes instantly drew towards the direction the enemy was coming from. 

"They are coming," a bestial smile appeared on Layn's face. Even though he wasn't a warrior, the call of blood reinforced by the blood weapon spell was more than enough to turn him into one. 

"We are prepared. There is no need to..." Castor couldn't even finish his words. Layn's artificial thirst for blood was too great for the archmage to stay in his position. 

"KILL!" screaming from the bottom of his lungs, he lunged forward. The blood of the man he killed turned into energy, energy Layn used to rush ahead. 

Just when the attacking party finally decided to take down the illusion that hid their movements so far.