"What the hell is this thing!? No matter how many times I cut it, it regenerates immediately!"
On the lowest level, near the center of a large, empty floor, Xerius, a man in white armor, was alone, battling the alien form in front of him.
The size of the floor was beyond comparison for Xerius.
It was a little larger than a modern-day dome stadium.
As soon as the battle started, Xerius's friends stopped moving due to the demon's rush.
There was no time to check on them, but Xerius decided that they were probably dead. That's how immobile they were.
It was more powerful than any demon they had encountered so far. It's also an order of magnitude larger.
It was also a monster that Xerius, who was not familiar with demons, could not identify.
The demon was tens of times larger than Xerius.
If you compare the size, it is as long as three large carriages stacked vertically, and as wide as ten carriages side by side.
On top of the body, which had a round shape like a bun with four thick legs, were seven long necks.
The ends of the necks were snake heads, each moving as if they had an independent will.
It had the strange appearance of an tsuchinoko with multiple long necks.
――The sound it makes is unpleasant. First of all, snakes are not creatures that make noises!?
Each head cried out in its own way, and the roar that reverberated through the room struck a nerve in Xerius.
As a tantrum-prone man, Xerius reacted more strongly than the other humans.
Xerius combined his sword skills and magic to cut off several heads, but he was helpless in the face of the demon that kept regenerating even after he cut it off.
He tried to attack the main part of the creature, but it was covered with hard scales that prevented him from using his blade.
Wearing white armor, Xerius wielded his sword as if he were dancing, and regardless of his personality, he was also very elegant.
It was a unique sword technique handed down in Xerius's family, a sword that focuses on defending against enemy attacks and using its power to attack.
――I'm tired. What am I supposed to do? My energy is dwindling.
And the smell of this demon's breath: ...... This is probably poison. I just inhaled a little bit, but I feel like my body is going numb.
――All my friends were already dead. I had left the recovery from the poison to the others, so recovery was hopeless. I'm not very good at that kind of support magic.
Right in front of me, right in front of me, is the final point of the dungeon!
Xerius gazes at the huge door behind the demon.
A gorgeous golden door, like a treasure house. It was obvious that it had what he was looking for.
There was no way to open the door without ignoring the demon.
Despite their dull appearance, demons move fast.
The movement itself was simple, just rushing towards Xerius.
But even a simple movement is nothing more than a threat if there is a difference in ability.
If he was stepped on, his armor would be crushed.
"Am I, am I going to die here!? All alone in a place like this, with nothing to become!?"
He wanted to avoid the onrushing demon, but he couldn't move from the knees down.
Conscious of death, Xerius shouted loudly. No one responded to his empty howl.
――Dying. For what? For what I've done all this time!
I have to become a hero!
I have to be special or no one will recognize me. ......!
Despite Xerius's intentions, his body had reached its limits due to the long march and battle.
Moreover, he had been unknowingly poisoned by a demon.
The entire floor, filled with the exhalation of the demon, was already under the demon's spell.
On the verge of colliding with the demon, Xerius desperately held his sword in front of him and used it as a shield, but his small resistance was in vain and he was blown to the side of the wall.
Xerius was blown away so easily that he was no different from pride in the air.
The last thing that popped into Xerius' mind was the image of Hazuki, who had followed him without a word, no matter how rough Xerius had been with her.
――Damn. Am I wrong ......?
The sound of Xerius' sword and armor clashing reached the ears of Mars and the other three people above.
"Hydra. ......! W-Why is there a demon like that in the dungeon!? It should have gone extinct a long time ago! ――『Poison Decomposition』! Both of you, stop breathing so heavily!"
Lilia, who landed on the lowest floor after Mars, shouted in a hushed voice and immediately covered the three of them with magic that purified the poison.
The demon that Lilia had called Hydra had walked up to the armored man by the wall without noticing Mars and the others.
The floor was the size of a dome stadium that he had once seen.
An overly huge door in the distance caught Mars' attention.
"Xerius......!"
When Hazuki saw Xerius moving faintly, she tried to run to him, but Mars stopped her.
"Lilia. Tell me what you know. While we're still unnoticed."
"X-Xerius!"
"Hazuki-chan, shut up for now. I need information to help him. I can't help him if I get hit by an attack I don't know about. If I'm dead, you get out of here."
Mars could not be so mild-mannered.
It was different from the demons he had encountered in the past. It had the same air as the snake demon he had encountered in [Ganymede].
He glanced around the floor and saw two dead bodies lying around.
Xerius seemed to be barely alive, but with the demons on their way, it was only a matter of time.
"The Hydra is a resilient monster with near immortality. ......! Even if you beheaded it, it would be pointless, it would regenerate immediately. And even its breath is poisonous. ......! My magic is keeping it at bay for now, but it's only a matter of time.、――Just being here is killing me!"
"All I see is poison, and the dungeon boss is ...... How do I beat him?"
The snake in [Ganymede] also used poison.
However, the snake demon did not spread its venom to affect its surroundings, but only poured it on its prey.
The venom that dripped from its fangs simply melted the floor and walls.
"Take him down!? We must retreat immediately! It looks like a snake, but it's a member of the dragon family, you know!? It is a demon that should have been exterminated long ago! Why is it here!?"
"You grew up in a greenhouse where there were only weaker people than you. ...... I've never seen one, but I'm sure there are dragons. ...... So Lilia, do you know how to defeat them? Should I do it with just a sword?"
The only things that Mars feared in this world were the dragons he hadn't seen yet, his own brother in this world, and the wrath of Lilia.
The existence of dragons seemed like a fairy tale at first, but in a world with dungeons and demons, it was very real.
"I don't know ...... how to beat it. I just read about it in an old book. ...... ――W-wait! I think it said that when it was defeated a long time ago, the deciding factor was a wound to the torso! That there was some sort of nucleus!"
It was thought to be an immortal creature, but it has a nucleus in its torso.
When the Hydra was wiped out a long time ago, its core was uprooted and destroyed in its juvenile stage.
"The only way to stop regenerate it's neck is to smash the ...... nucleus. ...... Lilia, Hazuki-chan. Can you blind all the necks, just enough to blind them? A bow would be helpful if possible. Just because they regenerate doesn't mean the arrows go away."
――He only needed a moment of time.
Mars is confident that he can manage with that much time.
"T-Then, I'll use fire magic to blind it, and Lilia can shoot it's eyes out while I do it. ......?
"Okay. Lilia, can you do it?"
"Don't ask me if I can do it or not, just tell me to do it. ――I can do seven in a row, twice."
"That's Lilia. Everything is perfect. ――Now, I'm going to draw him in, and as soon as he gets close enough, Shoot Hydra in the eye, I want you to cover your ears and open your mouth. It's going to make a lot of noise. If you have any magic that can muffle the sound, use it."
Hazuki made a face that said she didn't understand what he meant.
Lilia looked as if she had figured something out and nodded quietly.
"I-I can use the magic of volume reduction, so I use it, right? ――So what will Mars-sama do ...?"
"It's a given. I'm going to beat its. You'll see. ――I'll show you the real [Thunder]."
Puffing, Mars turned and shouted at Hydra, who was walking toward Xerius.
Lilia and Hazuki couldn't believe their eyes when Mars put the sword back on his hip that he had pulled out.
On the contrary, he wrapped the cord of the scabbard around the flange to prevent the sword from falling out of the scabbard.
"Come here! Come here, You fool!"
Two of the seven heads of the Hydra turned and extended their tongues in a shrill shriek at the full force of Mars' shout.
"Ooooiii! It's new food! It's fresher and healthier than that white stuff over there!"
With a wave of his hand, Mars made his presence known to Hydra.
――Xerius will still be able to help. I don't like him, but I'm not going to ignore him. I'm sure he's feeling some remorse.
"M-Mars-san?"
"Hey pervert. Get ready. ――It's coming right at us."
Lilia takes out seven arrows from her arrow canister and draws them on the bow held at her side.
Since she is not sure if the normal arrows will pass through the membrane of Hydra's eyes, Lilia grants most of the magic power she can pour into them.
She usually just shoots, but when it comes to serious fighting, Lilia's style is to use magic as well.
When Hydra's head turns toward Mars and the others, its entire body also turns toward Mars and the others as its head crosses the majority.
Then, with a thud, Hydra rushed forward at full speed.
The speed was unimaginable from its physique. It was as if a huge dump truck was approaching at full speed with hostile intent.
"I think I can only stop it for a moment! Don't miss it, Lilia! ――Red Lotus Formation, [Blaze of Fire]!"
Pointing her staff at Hydra, Hazuki shouts the name of the magic with a serious face.
Mars feels a little embarrassed, as if it were a game. But in the serious atmosphere, he can't say that.
"Who are you to talking about me you pervert. I am an elf, a natural-born master of the bow. And I am the descendant of the one who has the most courage and supremacy among them. ----Grant Archery [Meteor] Seven Piece.
Hazuki's wall of flames covered Hydra's entire body, stopping its only briefly.
While Hydra was repairing its injured body, Lilia fired seven arrows at the same time, destroying one of the eyes on each of the seven necks.
The arrows flew at an unbelievable speed, emitting a white light.
There was only one wind noise when they were fired.
――Wow, ......! I think it's faster than a gun, maybe.
The name [Meteor] is not an understatement: .......
Malus is dazzled by the personal technology that surpasses modern technology, but he makes sure to observe the landing.
"More to come! Seventh series, number two! Sink into the darkness! ――Mars! I'm counting on you!"
An arrow pierced both of Hydra's eyes.
Even with its excellent restorative abilities, The hydra is unable to eliminate the foreign objects lodged in its body.
Upset by the pain and lost vision, Hydra comes to a complete stop in the center of the floor.
Being in the middle strengthened his presence.
"Copy that! You two, cover your ears!"
"Yes! [Deafening]!"
After releasing the magic, Hazuki pushed Lilia down to the ground and hugged her, covering her ears with her whole body.
She knew that her hearing was stronger than hers, so her body unconsciously moved to protect her.
――This pervert woman .......
Lilia mumbled in a quiet voice, partly because she was having trouble hearing and partly because her face was under Hazuki's chest.
It was a word she knew she would never say to Hazuki.
"Thank you. ......"
"What did you say!?"
"Nothing!"
Hiding her embarrassed face behind Hazuki's body, Lilia covered her ears.
"――『Body Strengthening』『Body Strengthening』『Body Strengthening』……『Hypersensitization』、『Pain Dulling』……I'll be sore all over tomorrow."
Mars steps toward Hydra, who has stopped in its tracks.
In an instant, Mars shortens the distance to over a hundred meters.
To the untrained eye, it looks like an instantaneous movement.
Even though he is moving at such a high speed, Mars is able to perceive everything.
He is able to perceive the slightest movement of Hydra, the appearance of Hazuki and Lilia in the distance, how much force is put into his legs, how much his clothes flutter, and so on.
All of the magic that Mars used could be called rudimentary.
Ordinary people are not aware of the natural act of walking.
In the same way, the inhabitants of this world do not try to master the rudiments of magic.
They use 『Body Strengthening』 as a matter of course, but they are far from the extreme.
The first thing Mars did when he realized he had reincarnated was to learn about himself.
He sought the answer to his reincarnation not outside, but inside. This was a result of his original introverted personality.
He contemplated the parameter of magic power, which he did not have in his previous life, and the benefits it brings.
Only Mars, who has a modern sense of values, knows how powerful magic is when it comes to "Strengthening the Body," which is taken for granted.
It would not be a shame to pour all of his magic power into it, Mars thought.
If I had to sum up Mars' ability in one word, it would be supernatural physical ability.
It was understandable that he would try to pursue flashy magic. In fact, Mars was not unmoved by it.
But a physical ability that can treat a top athlete like an infant can be applied to anything.
Mars spent seventeen years developing a magic that many people would have abandoned as soon as they mastered it.
In the end, there was no room for other magic, but Mars was satisfied. There's nothing to be afraid of.
After seventeen years of pursuing a single magic, Mars has become a being who can completely grasp every movement of his body and control every single muscle fiber at will.
Because he moves with only the minimum amount of muscle, he is less fatigued than normal people. Even natural healing can be controlled to some extent.
The kinetic vision gained has been enhanced to the point where objects appear to stop moving, and the body, where there is no lag between thought and actual action, makes everything happen.
Whether you are caught in a trap and arrows are flying at you, or you fall into a pit, you can avoid it with your physical abilities alone.
"One more time: [Body Strengthening].! ――I won't let you suffer. Just for a moment. We'll share the pain. I'm in pain too."
Hydra does not notice Mars, who suddenly appears right beside hydra.
Mars kept the sword at his waist in its sheath and swung it like an iai at Hydra's side.
It was not enough to slash. The only way to destroy the nucleus, whose location was unknown, was to smash its entire body.
He sheathed his sword, intending to use it as a blunt instrument from the start.
With a thud, the sword struck the body part of Hydra.
As Mars' sword swung, there was a whooshing sound of air splitting.
The next moment――
Boom, boom, boom! and the sound of an explosion echoed, shaking the entire dungeon.
It sounded as if thunder had been generated inside the dungeon.
The sound echoed outside the dungeon, and the labyrinth city trembled with fine vibrations.
The Hydra exploded on impact, scattering and sticking to the walls of the floor.
No matter how good its regeneration ability is, it can't regenerate if its core is destroyed and its whole body is turned into a part of the wall.
It was neither gunpowder nor magic, but a pure impact explosion.
――That's why He's called the [Thunder].……This sound was heard outside.……。
Lilia learns why Mars is called [Thunder].