It happened when Kayn had already eaten three-quarters of the souls on the battlefield.
It was certainly the biggest harvest Kayn has ever gotten ever since becoming a demon.
With so many souls, his mana pool and comprehension of how to mana shot up significantly as he grasped the way how to cast more complex spells.
But he didn't have time to create any more new spells, as he hadn't thought of one yet. He only got the comprehension to do so and more freedom with his larger mana pool.
And Kayn would have to invent new spells on the spot when his nose smelled something familiar.
Kayn flew up and turned towards the direction from which the wind had flown before.
It was quite a surprise for him as he didn't expect the wind demon to come back, or at least not soon, but what really caught the attention of his nose was not the scent of the wind demon's soul.
It was the scent of another army of demons approaching him from that direction.
"Not only did he decide to return, he even brought another army of demons with him… I should have forced myself to end the wind demon before. This is getting on another level of annoying."
Kayn flew up and closer towards the source of the smell, and then he saw it.
The wind demon didn't fly like before, but instead, he walked in front of the army, behind a single demon, a demon that had the scent of earth emitting from his body.
"Another earth demon? Perfect! They will fucking defend against all of my attacks now!
Kayn sensed the incoming headache from having his frozen wind being blown away by the wind demon and his spears blocked by an earth wall, and he began to consider just leaving the damned fortress and coming back another time.
But as his thoughts were already filled with new ways to use his ice affinity mana, and a larger pool of mana that enabled him to do more 'ice-demon-cheat-like-spells', Kayn decided to play around with them a little more.
As Kayn moved just a tiny bit closer, he soon locked eyes with the wind demon again as the yellow demon could somehow instantly detect him even from far away.
"Does he like a radar or something? This is the second time he discovered me so fast."
But different from last time, the wind demon didn't fly up the second he saw Kayn and instead walked beside the earth demon, seemingly talking to him about something.
The earth demon then also turned his eyes towards Kayn, his eyes even more vigilant than the wind demon's.
To test things out, Kayn used his patented, original spell, the ice bullets, as he sent them out everywhere towards the second army that came to fight him today.
And Kayn certainly didn't expect that the reaction of the earth demon was even more prepared than Kayn could have even thought of.
Instead of casting an earth barrier in front of him to defend against the bullets, the earth demon cast two spells simultaneously.
One spell brought up a long earth wall that spanned the whole army, while the other spell created a hole on the ground right behind the earth wall.
The demons all soon entered the hole and hid behind the tall earth wall, creating a perfect barricaded trench for them to defend against the ice bullets.
While the earth demon himself didn't move from his spot as the wind demon just cast a wind shield to protect the two of them from the bullets.
"Yup, fuck me. Not only did the damn wind demon spill out my spells, but an earth demon is actually the perfect partner for the wind demon to make the proper countermeasure to the spells that the wind demon couldn't deal with easily.
Curse them, I'm taking this back to the fortress."
Kayn realized how annoying the trenches would be if he were to force a fight here and try to deal with the large number of demons, so he decided that they would be the ones coming to him instead.
Even if they created these trenches in the area around the fortress, they wouldn't be able to just stand inside the trenches all the tim,e as they were the ones who needed to attack Kayn instead of the other way around.
With that thought in mind, Kayn began turning and heading back towards the fortress.
But of course, he didn't just leave like that. He left another gift for the army.
"Fortified Ice Spear."
Kayn only had 4 fortified ice spears and threw them in different directions as he flew away from the two elemental demons and the army.
One of the spears flew straight in the earth and wind demon's direction, and the wind demon quickly told the earth demon to defend with all he had.
The earth demon was skeptical at first, but as he felt the dense amount of mana contained in the ice spear flying towards him, the earth demon didn't hesitate for a second as he conjured an earth wall.
One that needed all his focus to do, and was three times thicker than an ordinary earth wall.
Even with the unnecessarily thick wall that the earth demon had never conjured before, the ice spear still caused a large boom as the thick wall crumbled into pieces.
The ice spear even stood as it held its solid form, stabbed into the ground where the earth wall used to be.
Not only that, three more ice spears also made their way towards the ordinary earth wall that protected the ordinary demons, easily piercing the ordinary earth wall.
With a large hole on its body, several parts of the wall began crumbling as they fell onto the demon that hid under them.
Fortunately for the demons, the earth wall was an ordinary one, and it was anything that was heavy enough to kill a resilient demon's body.
Only a few demons were injured from the attack, and the army essentially didn't lose any fighting strength whatsoever.
But the earth demon stood still and stared at the ice spears that still emitted a freezing aura to everything around it, even when the caster was already long gone.
The crumbled pieces of his strongest wall also told him about the strength of the ice demon that he was about to fight.
The earth demon then turned to the wind demon.
"I understand where you are coming from now. I will prepare the units.
We will do it."