It happened on the afternoon of the day when I became sisters-in-law with Lenalee.
"All members of the medical department, please assemble. Director Reitalyu has an announcement to make."
"Understood."
Reitalyu summoned us after lunch.
It seems there is something important to discuss.
"Thank you for gathering despite being busy. Also, thank you for always working energetically."
"Yes, Director!"
"I have something very important to tell you now. Everyone, listen carefully."
When everyone gathered, wondering if she had a new lover, Reitalyu began her speech in a formal tone.
She had a very serious expression on her face, which was unusual for her free-spirited personality.
"Today, the operation to seize the Bueri Mines has been launched. A large-scale battle is about to begin, and many casualties are expected."
"Understood, Director."
"And most importantly, from today onwards, those who are involved in treatment are required to wear special equipment. Everyone, please come to the headquarters to get it by noon."
Reitalyu announced that the "Mine Seizure Operation," which Verdi had previously mentioned, had been implemented.
Rumor has it that this battle will likely decide the war with Flamer.
It is said to be a very large-scale operation, so a sharp tension ran through the surrounding medics.
"If the operation fails, is there a possibility that the enemy will attack us here?"
"Generally, it should be okay. But you never know what might happen, so be mentally prepared for an emergency."
The Bueri Mines is Flamer's lifeline. Losing them will almost guarantee defeat.
If the mines are taken, they won't be able to mine iron, and the supply of guns will stop.
"This battle is going to be the largest since the Defense of Winn."
"…"
"The key to Austin's victory will be how well the medical department can help its allies. Let's all do our best."
With that, Reitalyu made a smile and encouraged us.
The medics responded to this encouragement with a battle cry.
─────However, for some reason, Reitalyu's complexion didn't look good.
***
On this day, we finally launched our invasion of the Bueri Mines, which was being guarded by a weakened Flamer army.
Flamel will have to accept unconditional surrender if this place falls. Austin is finally on the verge of winning this war.
Although Flamel was in such a desperate situation, the morale of the soldiers was by no means low.
In fact, it could be said that it was higher than ever before.
This battle was seen as a great opportunity for Flamel to turn the tide.
The Bueri mines were naturally fortified with steep inclines and rough paths.
Manpower was sufficient, and with the help of the miners, digging trenches could be done freely.
Also, by moving through the various tunnels within the mines, the positioning of soldiers could be adjusted flexibly.
Moreover, in the close-quarters combat within the narrow mines, the range of guns didn't matter much.
This would allow them to mask the technological gap between us and the Flamer Army.
Flamer could not have asked for a better defensive position.
So when Flamer became aware of Austin's movements, they gathered almost all their remaining forces at the mines.
They aimed for a decisive battle, hoping for a sudden and complete victory.
This situation was similar to the previous Battle of the North against the Sabbath.
It's the same as when Austin, who was at a disadvantage, gathered together its forces and took a gamble to engage in a decisive battle with the Sabbath.
From Flamel's perspective, our risky attack on the mines was exactly what they wanted.
Given these circumstances, why did Austin attack the mines?
Furthermore, why did they make the operation public instead of keeping it secret?
Was it a sign of confidence from a strong position, or was there some ulterior motive?
The reason for this became clear when Austin's offensive began.
***
"…Something's wrong."
The evening of the day the decisive battle began.
Hardly any of the wounded were brought to the hospital.
The hospital beds are usually filled to capacity on the day of an offensive.
However, on this day, only a few soldiers were brought to the field hospital.
"Help me, medic! I can't breathe, my eyes feel like they're burning."
"What is this…?"
Moreover, the Austin soldiers who were brought in did not have any gunshot wounds.
What they complained of were overwhelming coughing, runny noses, and vomiting.
Tears streamed from their bloodshot eyes, and they kept coughing as if they were about to vomit.
"Help me, medic, I'm dying. I'm going to die."
"Get an oxygen canister! He is showing symptoms of oxygen deficiency."
I had never seen patients with such symptoms before.
However, the soldiers who were brought in all complained of similar breathing difficulties.
"Touri, could you prepare water in a bucket? …Nurses, remove the clothes of the wounded and wash their bodies with water."
"Director Reitalyu, what are these symptoms?"
"And please wear this mask when you treat them."
Reitalyu did not panic when examining these patients. She only sighed quietly.
She wore a large mask that completely covered her face and handed out masks to us as well.
From a wooden box that had been prepared in advance by the bedside.
"This mask…"
"It's equipment to prevent inhalation of poison gas. As I announced this morning, everyone involved in treatment must wear one."
"…Poison gas?"
"Yes."
Seeing the shape of the mask and the pained expression on Reitalyu's face…
I realized Austin's military had used a terrible weapon that should never be touched.
***
Chemical weapons. These were weapons prohibited by international treaties in my previous life.
When I was living in my previous life, I always wondered:
Shooting people with guns or cannons was fine, so why were gas attacks prohibited?
Even though they are both weapons that kill people, why are guns allowed but gas isn't?
────To understand the reason, you have to see the suffering patients in front of you.
The reason is very simple.
It is because they are too inhumane.
The developer of this chemical weapon was Takuma.
He was involved in the development of antibiotics and helped establish the temporary medical department in Marshdale.
He was a genius familiar with both medicine and chemistry, affectionately known as Mr. Kuma.
The military had repeatedly approached him about developing chemical weapons.
However, Mr. Kuma initially refused to cooperate, saying, "I'm not doing this research to kill people."
His stance was: "I refuse to research killing people but I will help save soldiers."
That stance changed after the Sabbath refused our unconditional surrender.
He began to delve into chemical weapon research as if he had become a different person.
He was a kind man who was so terrified that his family would be killed that he sold his soul to the devil.
It was already known that toxic gases could be produced in soap factories.
Mr. Kuma, who had treated gas exposure victims, knew it could be used in warfare.
After much effort, he succeeded in developing the technology to mass-produce and can this toxic gas.
Thus, Austin succeeded in developing the world's first chemical weapon.
Handling this chemical weapon was difficult, and there was a significant risk that Austin's soldiers could be affected by mistake.
Therefore, Mr. Kuma visited the frontline field hospital to explain the gas weapon and treatment methods beforehand.
─────And this was also why Austin leaked the attack plan on the mines.
Austin wanted as many soldiers as possible to gather at the mines.
So that we could catch them all in one fell swoop and kill them all.
Austin's military never intended to launch a frontal assault on the mining area from the start.
All they wanted to do was gather enemy soldiers together and calmly release the gas.
Using the bait of attacking the mines to gather the enemy together.
The power of the gas was immense.
The toxic yellow-green smoke released by Austin's soldiers was carried by the wind, slowly flowing into the mines.
That first blow from one of history's most vicious weapons caused devastating damage.
Since the gas is heavier than air, it naturally flows into the trenches.
There was no escape for the Flamer soldiers hiding in the trenches.
As a result of the gas filling the trenches, most soldiers holed up in the trenches suffocated to death.
It was an impersonal and cruel slaughter akin to magic.
However, this gas attack did not yield the desired results from Austin's perspective.
While the gas weapon was devastatingly effective against Flamer soldiers in the trenches,
It did not reach the higher ground and had no effect on the enemies at the top of the mountain.
The gas did not climb the mountain, instead splitting left and right at the base, slowly dissipating.
The military, which had been hoping to take over the mines in one sweep, was forced to change its strategy.
Nevertheless, simply suffocating the frontline Flamer soldiers might have justified the cost-effectiveness.
This wiped out several layers of enemy trenches at a much lower cost than preparatory bombardment.
***
"Just like pest control, isn't it?"
These were the words of a soldier who secured the trenches dug by the Flamer soldiers after the gas attack.
Inside the secured trench, there were many pale, dead bodies giving off a foul odor from gas and vomit.
Most of them had died on their backs, as if they had fallen out of the trench.
It was just like after a farmer had fumigated for pest control.
"They look like flipped-over locusts."
"Serves them right… Ah, I'm glad I'm in the Austin Army."
Why did the soldiers die lying on their backs?
This is called orthopnea. When pulmonary edema is caused by gas, it's easier to breathe while sitting.
In the gas-filled trenches, the enemy soldiers were probably coughing and vomiting, looking up at the yellow-green sky, trying to sit against the trench walls.
But they were suffocating, their strength failed as they fell back, dying as they looked up to the heavens.
It was a cruel end for soldiers who had bravely gone to the battlefield with determination.
When the Flamer army saw this chemical weapon, they showed almost no resistance and fled in disarray, being driven up the mountain.
This was no battle; only the scene of Austin releasing gas and Flamer soldiers fleeing in panic.
So was the field hospital idle then? Not at all.
At night, Austin soldiers who had been exposed to the gas were brought in one after another.
Most of them were soldiers who had secured the trenches after the gas attack.
They had apparently taken their masks off on their own judgment.
The gas remains thick in the soil in the trench and on the bodies of enemy soldiers, lingering for some time.
Prolonged exposure to the gas can make you sick even at low concentrations.
Unaware of this, the soldiers took off their masks after securing the trench, saying, "It obstructs vision and makes it hard to breathe."
As a result, the field hospital was overflowing with soldiers suffering from mild gas exposure.
They lay in agony in their hospital beds, coughing wetly and coughing up phlegm that was tinged with light blood.
Whether they die or survive, gas victims suffer for an exceptionally long time.
The soldiers were sobbing and thrashing about, and some even cried out to be killed.
Their throats burned painfully, their eyes stung as if salted, and every breath brought up more phlegm.
It was as if they were being tortured…
"Little Boss, how's the patient over there?"
"…No good, they've passed away."
"I see…"
Suffocation is one of the most painful ways to die.
Severe cases saw soldiers scratching at their throats, writhing in agony until they passed away.
Even mild cases were hard to fully recover from, leaving soldiers to live the rest of their lives feeling breathless.
It was then that I understood very well why chemical weapons were banned by treaties in my past life.
"It's a wonderful method of attack. We've advanced the era once more."
"From now on, we'll need to mass-produce gas masks so that we won't have any problems if the enemy uses gas in the future."
"Exactly."
Unaware of the suffering of these soldiers, the higher-ups in Austin's military, hearing only the damage reports as numbers, and were delighted with the results.
They praised this weapon which could kill people safely and cheaply.
"Takuma has created something truly amazing."
"Austin can continue to be at the forefront of the war thanks to him."
…From here on, the war shifted from "how to defeat the enemy" to "how to efficiently kill people."
This might have been inevitable with Austin's limited military strength.
But technological advances didn't only benefit us.
I believe this offensive on the Bueri Mines marked the point when the war changed from "combat" to "slaughter."
Technological progress, the development of weapons of mass destruction, and the disregard for humanity.
Austin had become too accustomed to war, losing sight of many important things in the process.
Was it divine punishment, or is history destined to follow the same conclusion?
Austin would soon pay the price for developing this poisonous gas.