Ground battles had many limitations; no matter how wide the plain was, many monsters could not pass through due to obstacles such as mountains, seas, and cliffs.
Moreover, there were not many monsters that drilled through the ground, so all that he could fight were monsters with their feet on the ground. There was no need for Hundred Eyes to even act.
The air is different. Although only flying monsters could fight aerial battles, any and every monster that felt the fortress's mana wave would try to join the fight. Their attacking directions weren't limited to the front, back, left, and right; they also included up and down, which would expand the battle area severalfold!
Monsters were everywhere. Perhaps all the monsters that could fly were gathering in this area, as the sun was nearly blotted out. There were just that many monsters converging on a single target: the flying fortress.
[Though, usually, one would be in despa....kyaaaaaak!]
"We'll go even faster from now on."
Usually, it would consume a lot of mana to move an artifact this big, very fast. This was also why Yu IlHan had put his heart into building the engines that levitated and drove the flying fortress.
However, the 4th option enabled sudden acceleration, sudden rise, and sudden lowering, and did not place much pressure on the engine. The amazing thing about this option was that it required little mana!
"Sudden acceleration!"
When Yu IlHan willed it, the barrier enveloping the entire flying fortress vibrated again. Like that, the fortress itself practically became a giant bullet and charged against all the monsters up front!
It was quite strange, whether it was seeing Yu IlHan order the flying fortress as if ordering a Pok*mon to body slam, or seeing the flying fortress actually obey his orders.
[The scale is way too big!]
"Go!"
[Kihik!]
[Kihiiiiii!]
[Something is coming!]
The enormous size, weight, and vibrations, combined with its speed, made it impossible for even the flying monsters to dodge.
Moreover, even if they could dodge if the flying fortress was only charging forward, it also emitted mana waves and physical vibration waves, dulling the monsters' movements!
[Critical Hit!]
[Critical Hit!]
The moment the large swarm of aerial monsters and the flying fortress collided, countless 'critical hits' etched on Yu IlHan's eyes. However, he ignored them all and ordered another sudden acceleration, and the majority of the monsters charging towards the fortress were smashed apart like bowling pins.
[...How many just died?]
To Liera, who asked with a pale face, Yu IlHan replied nonchalantly.
"Around 30,000 in the two accelerations."
[Thirty thousand...]
If there was a disadvantage to physical attacks, it was their limited range, unlike magic, which could burn an entire region. No matter how large a Pokémon body-slammed, they couldn't attack more than several Pokémon at once.
However, Yu IlHan ended up enlarging the attacker's body to overcome those limits. The XXXXXXXL-sized cannonball's overwhelming surface area had become a splendid weapon!
Liera thought that Yu IlHan had perhaps made the flying fortress precisely to slam into everything.
[How long would it take for the monsters on Earth to be wiped out...?]
The sudden acceleration didn't just end with twice. The continuous charge attacks cleared most of the mobs, and after that, Yu IlHan activated Hundred Eyes to take care of the 4th-class monsters that didn't die so easily.
"Activate Hundred Eyes!"
[Is there some kind of magic that amplifies their function if you shout it out loud?]
"No, but I feel better."
[How honest.]
Hundred Eyes, which had been obediently recharging mana after being used on the ground, received Yu IlHan's will and began moving again. However, their directions were different from last time. Their orbit was larger, and they were also much farther apart.
[Huh? The orbit changed.]
"This should be the norm. The destruction mirrors do not need protection from the fortress. No, to be exact, it must not receive protection from the fortress."
Yu IlHan's original idea had two orbits for the Hundred Eyes. First was a small ellipse within the fortress, with the mansion as the center. This was the ground-battle mode.
This made it possible to protect the mansion, but made it difficult to attack outside the fortress.
And the second was to orbit the surface of the barrier protecting the fortress.
Destruction mirrors had the splendid ability to shoot mana stored in them, but their core ability was to suck enemies' mana and reflect it back. However, inside the fortress, it was difficult to bring that ability out to its fullest. These things must grow outside while getting beaten up!
[Now that is really like a flying fortress.]
"It was like a flying fortress from the beginning though."
The scene of a hundred gigantic mirrors orbiting the fortress, as though satellites orbiting a planet, gave them a feeling like no other. Liera grew slightly proud, as this was something she rarely saw, even in Heaven.
However, would she be able to hold on to those thoughts after seeing what happened next?
[He is there.]
[He's the one that mercilessly massacred our kin.]
The monsters that were able to dodge the charge with ease and those with high mana resistance tried to invade the fortress after it fell quiet, but the destruction mirrors on the surface of the barrier blocked their paths.
Naturally, the speed of these destruction mirrors wasn't possible without support. The vibrating barrier was supporting their movements.
[Kihiiii!]
[Erase and destroy.]
These enraged-for-who-knows-what-reason monsters tried to destroy everything in their path. But that didn't mean that they didn't know of the dangers of the destruction mirrors; it was just that they wished to break whatever blocked their paths and proceed forward!
[Kuoooooooh!]
However, disaster struck them. The destruction mirrors sucked in their health and mana upon contact, amplifying them before reflecting them back as an energy beam. This time, the scale of the attack was much larger than when the fortress was on the ground!
"Go! Kill them all!"
[Wow...…]
Energy beams, resulting from the power focus of the destruction mirrors, extended from the sky to the ground, piercing everything in their path. A hundred such battles were occurring simultaneously, so it seemed as if light were raining from the sky.
It was a spectacular, but rather sad scene.
"How is it, a much better picture than on the ground, no?"
[How beautiful... Though, the results wouldn't be so…]
Muttered Liera. And she was correct indeed.
[Critical Hit!]
[Critical Hit!]
[Kihik!]
[I cannot see in front of me!]
[My eyes, my eyes!]
[Kuaaaak!]
Even the monsters in the hell dungeon he had been to wouldn't come out unscathed after being struck by these beams. There was no way these beginner-level 4th-class monsters could remain intact after the beams, even if they managed to dodge the flying fortress's charge.
Screaming in pain was the same whether one was human or monster. In this wide stage known as the sky, a symphony of monster screams resounded.
[Kuaaaaaaah!]
[Higuh, Hguoooooooh!]
Blood, flesh and bones scattered everywhere. The lucky ones died instantly, but the unlucky ones had to roll around in pain after having lost the majority of their bodies. Although he'd have an easier time killing them if this were on the ground, the fortress's air-based location meant he couldn't do much about the falling monsters.
Fortunately, Hundred Eyes would stay active until the monster was killed or it ran out of mana, so it did not care whether the monsters fell to the ground or shot up into the sky; it just chased them until they met their end under its beams. To the monsters, this was no different from hell.
Though not as fast as the fortress's charge, an absurd number of monsters were dying at an absurd rate. This was even more amazing, considering that the majority of them were late-stage 3rd class or beginner-stage 4th class.
"Good, even the fastest aerial monsters cannot dodge, so I can conclude that this will be useful against all lower existences."
[I think this will work against 5th classes too....?]
"I'm not so sure. It won't be that easy, but perhaps it's possible if they're tied down somehow."
However, it was true that this was at the level of an apocalypse right here. There weren't many opportunities to fight 5th class, and the growth of the flying fortress hadn't ended, so it was well worth looking forward to.
Yu IlHan had checked enough that the Hundred Eyes were working properly, so he also unfolded Ruin Calling and flew up.
[You're going to move too?]
"The sky is different from the ground. Just the quantity of monsters is different. I should decrease them to save on mana consumption."
Of course, his objective was not only that. It was true that Yu IlHan had built the fortress to take care of Earth alone, but if he left everything to it, he himself wouldn't grow.
If he did not experience any growth, his skills would not develop, and if his skills did not develop, it would be impossible to attain 4th class.
He was gaining so much experience through this massacre, but if he lost the chance for all of that experience to be applied to him, then how frustrating would that be! He had to train his skills against these weak ones before the stronger ones popped out.
"Huiyaaaaaaaah!"
When he leaped beyond the barrier of the flying fortress, the monsters that were being tossed around by Hundred Eyes all looked at him. This guy just left his safe haven! – they thought that this was their opportunity to kill Yu IlHan.
And that was the worst possible decision they could make.
[It's him!]
[Foolish human giving up his own life!]
[Kill him! We will gain freedom once we kill him!]
They ran towards Yu IlHan faster than high schoolers coming out for physical education class.
Of course, many of them dropped out in the process due to Hundred Eyes, but even so, their numbers were so overwhelming that even Hundred Eyes couldn't shoot them all down. Really, it seemed like all of the aerial monsters on Earth were gathering in the sky above Korea.
"Fuu."
Yu IlHan leaped once more to go higher and laughed upon seeing various monsters charging towards him. Their incomprehensible hatred, as well as the strange and rapid development of Earth, was a blessing to him right now.
"Very well. Come on at once! I'll master these skills in a flash!"
[How about the blessing of the goddess of fire?]
"That makes me awkward, so don't ask."
[Yes, sir.]
Yu IlHan shut Liera up instantly and gripped his Eight-tailed dragon spear. Although he considered taking out Aegis, he found it too wasteful to use his sidekick...Aegis against that level of monsters.
Although others wouldn't believe this even if they saw it, Earth was only in the initial stages of the 3rd Great Cataclysm. More drastic changes would arrive soon, and the number of 4th-class monsters would also increase. It would be fine if he took out Aegis then. Right now, it was time for him to train the skills with his own body.
"Well then."
He wrapped his body in Eternal Flame and created Blaze atop it. Finally, he enhanced the mixed flames with Dragonic Blood, which he could use even now, far from Yumir, and a flame brighter than the sun covered his body.
[...Huh?]
Liera, who thought that Yu IlHan was using many flames at once to receive the blessing of the goddess of fire, voiced her doubt regarding another matter.
[Why can't the monsters find you all of a sudden?]
"Fufu."
Yu IlHan smiled, his body still enwrapped in brilliant flames that even 4th-class beings could not look upon directly.
"Being brighter than anyone else, and concealing oneself in front of everyone else. That can be called the realm of concealment meisters."
[Ah, uh, yeah... okay. So there was such a realm…..?]
Since no monsters could see him directly, his concealment skill automatically activated! The truth was always simple.
Liera thought that Yu IlHan's eyes were glistening unusually, but did not ask about it since she was a kind person.
"I'm going! You're all dead!"
The loner charged in the air while concealed, drawing a trail of bright fire. No monsters could find his figure, and that continued until all the monsters met their deaths in the air.
Truly a sad occurrence.