The demon tribe has appeared. This will be my first job as a holy knight.
　Tart and Dia, together with the two of them, headed to the site.
　...I knew it was going to be a slow carriage.
　Maybe next time we can build a primitive carriage. That's something we can build.
　The only problem is how to make it run over rough terrain.
　I'll see what I can do.

It's your first time. I can't wait to get it right.
''I feel the same way. Just remember that if the Demon Slayer's Warding fails, you'll lose at that point. If it fails, we'll be on the run.

Only a brave man can kill demons.
　That is such a creature.
　I created a magic that twists that providence. That's the only chance we have, and if the odds are overturned, it's the end.
　At that time, we will retreat.
　Of course, we won't just run back. I'm going to bring back the materials to find out why it didn't work.

Oh, yeah. That's the thing, though. I can do that warding for 30 seconds.
Are you sure?
Oh, it's awful to doubt. I'll show you later.

Even if it's thirty seconds, it's still a big deal that anyone other than me can use the Demon Clan Killing Technique.
　At any rate, while using the Demon Slayer's Warding, the magic power consumption is too drastic, and the battle power will be drastically reduced.
　If I can leave the activation to Dia, I can focus on attacking.
　Besides, if I can leave the field role to her, then I can assassinate instead of fighting.

''It's great. That, I wasn't good at all.
'Tart's in charge of physical combat and I'm in charge of magic. We're different in our specialties. Phew, I can't do everything like a rogue. No matter how many push-ups I do, I still have this arm.

Dia said, making a power hump, but her arms are too thin. And her two arms look pudgy and soft.
　I've been working out, but it's hard for me to gain muscle strength.

I've read the magician's formula for killing demons, and this magician's killer seems to be able to fly.
Do you want to fly?

Deere says with a bang, using her hands to form a gun. Cute.

'Yeah, now it's going to expand the field around the surgeon. But it's like firing a bullet like this, and then the compressed field flies off, and the field expands in response to the impact. You can make it like that. It just takes a fraction of the time, though. Maybe two seconds for me. I think a little over ten seconds is the limit for a rogue.

........I can't even imagine how in the world that would be possible if I altered the magic formula.
　But if Dia can do it, then I guess he can.
　The reason why thirty seconds became two seconds is because, unlike continuing to emit from its own point of origin, the amount of instantaneous emission is dependent on the amount of instantaneous emission as long as it is released as a bullet.

Then do it. You're going to be a lot of use to me. I just want it done by the time it arrives.
'I'll just do it. But don't hold your breath.

As soon as he said that, Dia unfolded the papers and started doing some calculations.
　Even though she told me not to expect it, I would expect it.
　In the meantime, I'll figure out a way to kill off the demon race in two seconds.
　.........Assassination has a few better success rates.
　But if there's a problem, there's too little information on the demon tribe that showed up this time. The data given to us by the state is very sensitive.
　This makes it impossible to formulate a plan. We'll just have to make up the missing information on the ground.

◇

After a few days, the carriage proceeded and arrived at its destination.
　It's a relatively large city in a regional city on the border with the neighboring country.
　Because of its location, it has prospered as a trading base.
　It's also a famous place for stone, and the beautiful stone streets are famous as a tourist attraction.
　Such a town is.....

It's like a jungle.
There's no one here.

It was covered in greenery.
　Ivy tangled around the stone-built houses, and trees cluttered the middle of the street.
　And yet, there was no sign of life.
　Not even insects, let alone animals.
　We stared at the strangeness from the entrance of the city.

Let's revise the material.
　At first, it seems it was just a single tree, which spread at a tremendous rate and swallowed everything.
　Those who escaped before the greenery completely eroded them were saved.
　The army went to rescue them, but none of them came back.

Then I heard that they tried to burn down the city's parasitic plants in one piece, but that failed as well.
　The trees don't burn with ordinary firepower, and even when they are set on fire, they have a powerful regenerative capacity, so it seems that they were almost ineffective.
　The operation failed, and every single soldier who was engaged in the operation was 'eaten by the greenery'.
　And when the incineration failed, the request came to me that it was likely the work of the demon race.

''Hey, Roug. Are we going in here?　If it's true that the greens ate you, then there are enemies all around.
'We have some things to do before we go into town. Tart and Diah behind me.

...I made sure of one thing when I accepted this request.
　Do we need to help the people trapped in the green erosion?
　The response is that the survivors are desperate and are willing to do whatever it takes. So we can be a little rough on them.

Of course, I want to save as many people as I can.
　However, I don't even know the nature of this forest, and I'm not going to rush in with nothing to show for it when I'm told that none of them will return.
　So, here, before we set foot in it, we'll need to experiment from the outside.

'Dia would see it, wouldn't you? She says there's one of these plants.
'Yes, they have magical powers in them, and they're all weirdly together. They can't all be one.
That's what I'm thinking. So I'll poke them. Keep an eye on the flow of their magic.

Experiment, part one.
　First of all, they throw warmed meat into the city.
　But there is no reaction.
　Next, they release a livestock pig that they bought on the way here into the city.
　That's when the pig entered the city and approached the trees.

'Pigi-ni-ni-ni-ni-ni!

The pig was tangled up by a vine that had grown from somewhere, several branches poking through it, squeezing it like some kind of joke, and eventually it was just skin and bones.

'Geez. So this is how the people of the city disappeared.
Trees eating living things... if there were such a dangerous tree in the city, it would have eaten everyone already.

Tart holds his mouth down.
　The tree eats him.
　And Tart is right, if they're this widespread in the city, no one will be alive anymore.
　This way, we can conduct our next experiment without a care in the world.

'Dear, see it with your own eyes.

Dia was watching closely, just as I had told her to. With the Touahade eyes I got from the treatment.

''When I ate the meat, my magic power swelled up. The pace of swelling is slow, probably converting the nutrients into magic.

In other words, we should think that these trees were released by someone to accumulate magic power.

'Okay, the first experiment went well. Two things have been learned. Next.

I toss a tarr filled with oil that I had prepared beforehand into the city.
　It rolls around and hits a tree that was standing in the middle of the street, blocking the street.
　At that point, there is no reaction.

A fire arrow was fired at the tarr.
　The barrel cracked and oil was sprayed on it, igniting it.
　It was specially mixed to burn. A huge column of fire is created.

I've heard it's a powerful regenerative ability, but I didn't expect this.
'But it's a normal regeneration. I don't think it's the kind of unreasonable restoration that the rougue said was characteristic of demons. It uses a lot of magic, so I'm not immortal at all.

It will be restored from the burning edge.
　But it is an enhancement and extension of the tree's regenerative powers.
　After a while, the flames are extinguished and the tree stands as if nothing had happened.

'If you can figure it out, good. Next time I'm going to do it with more flair, I'm going to burn it down.'

From my pouch, I take out a foul stone.
　This foul stone was also prepared for today.
　Normally, it is filled with magic power of the fire attribute, wind attribute and earth attribute in a certain proportion.
　With that, it was operated as an extremely powerful bomb that blew a large amount of wind into the flame, increasing its explosive power and scattering iron pieces.

However, this one was only flame and wind. It focused on explosive flames, not explosions, and specialized only in burning.
　With this thing, it could create a purgatory that could spread an ultra-high temperature over a wide area that couldn't be compared to a cup of oil in a tull.
　After all, it contains the magic power of three hundred ordinary magic holders.
　He fills the foul stone with magic power, it reaches a critical mass and begins to crack.
　They throw it.
　It explodes in the city.
　Red lotus flames spread out at once, engulfing a section of the city, and purgatory is revealed.

'Scary, but beautiful.'

Tart stared at the flames with a stunned face.
　After the flames were extinguished, the trees in the center of the flames had been burned to the ground, leaving the houses around them barely intact thanks to their stonework, their black shadows caked in.
　The shadows are the remnants of the trees that were entangled in them.

''These guys aren't the demon race itself, are they?
Yeah, maybe something created it in its capacity.

My suspicion was that all these trees were part of the demon race.
　But that's not the case.
　They are just tree demons that have the ability to regenerate extremely well. Perhaps they have the propensity to keep increasing in a grafted manner. So it was all flowing with the same magic power.

This fact has a gratifying and troublesome aspect.
　If it was a part of the demon race, it would not be able to reduce its numbers no matter what, since it would regenerate infinitely when it was burned using super firepower, but if it was just a demon with a powerful regeneration ability, it could reduce its numbers.

The trouble was that if we were connected to the demon tribe, we could trace it back there and find it, but since we didn't, we had to find the demon tribe that would be in this large city.

''Both of you, let's go into the city. Let's find the demon tribe.
Yes!　But isn't it dangerous?
'Yeah. We've burned a pretty large area, but there are still a lot of dangerous trees.
She'll be fine. As long as you're around me.

I move forward without fear, and an anxious-looking Tart and Dia stick around.
　They didn't attack me when I entered the city.
　That didn't change as we passed the section I had burned down.
　The trees didn't move even when I passed by at close range.

'What's the meaning of this?
I wonder if it's because of the rogue's use of magic earlier?
That's right. You experimented with it before you entered the city. First you threw a piece of meat and the trees didn't react. But they did respond to the next pig. Trees don't have eyes, they don't rely on sight to find their prey. The things to suspect are vibration, heat, sound, and breath. As for the vibrations and sounds, I excluded them because I didn't notice the flesh when it fell close to me. As for the heat, it's also ruled out because it was warming the first flesh to human skin. Then there's only breath. Or, to be more precise, the carbon dioxide you emit, that's what these guys' sensors are for.

The first experiment we tried was to see how they found their prey.
　The result is the carbon dioxide that the creatures exhale.

'So the rogue is hoisting the wind around it and sending it upwards.
'Yeah, that way the trees won't notice when they're this close.

I dilute my breath and fly to the heavens.
　With this level of magic, the automatic recovery of magic power will catch up with you and won't be painful.
　If you were to search for the demon tribe while being attacked by countless trees in a large city, you would be exhausted before you could fight the demon tribe.

Besides, there's a possibility that the trees share their senses with the demon tribe.
　If he wanted to take the initiative, he couldn't just play with the trees.

First, we have to find the enemy. The best way to do that is to do it before they notice us.
　If we do that, we will be able to get a head start.
　Let's move on.
　Fortunately, the trump card we have at the ready will be very effective against the main characters here.