Inside the Cave of Obscenity
Volume 5 Chapter 1: The Dawn of Decisive Battle

Several months have passed since the daughter of the hero, Mariabelle, and the others defeated the human-shaped slime in the abandoned Mythril mine.

At first, the daughter of the hero thought they would recapture their home country of Fonteau from the slime's control as soon as possible, but the slimes were far more numerous and powerful than they had imagined.

The slimes, with their magic and slight resistance to heat and ice, their weaknesses, lurked in the woods and fields to ambush the warriors and gain an advantage in the battle.

The Black Ooze was a mutant that took in the knowledge, abilities, and experiences of those who it took in and made them its own.

The slimes, the Black Ooze's children also have the same ability, and their knowledge was already beyond the scope of the weakest monster called "slime". They were so powerful that they could surpass even the strongest of mages, and the traps they set were based on humanity's instinct.

......In other words, instead of killing them immediately, they injure them, slow them down, and they even catch those who couldn't abandon and protected their companions.

People were not able to abandon others.

A man was poisoned by paralysis, injured―― they risked everything to save their companions, and those warriors who were protecting the injured were captured by the slime.

And so men were taken in and become food for the slime, and women were violated and turned into a nursery for more slime.

That was it for a few months.

The number of slimes kept increasing and the number of those who could fight them kept decreasing.

The only one who was a natural enemy of the slimes was the hero, his daughter, Mariabelle, the only woman in the world with black hair and eyes who could use the "hero's equipment" given by the goddess Fasalina, who continued to stand on the frontlines and destroy the slimes.

The number of slimes she had killed had exceeded hundreds and was about to reach one thousand.

It seemed pointless to count, and so she didn't know the exact number.

She just kept killing slimes every day and losing as many companions.

The hero couldn't do it all.

Her power could not reach all the battlefields, and the continent consisting of three countries was too large for her to fight.

...Still, Mariabelle continued to fight.

Her older sister, Meltia, possessed the same powerful magic like her mother.

Fenelieka was a monster who lent her power to the humans.

Fornelis was the warrior who defeated the Demon King with the hero.

Jenna, the priestess who supported the hero with her mother and Fornelis.

And many other companions.

The daughter of the hero came to be called "the hero," and her black hair and the flag of Fonteau became proof of the counterattack against the slime that was trying to capture the continent.

......A long time, several months, while understanding the hopeless power difference.

But she was still able to keep fighting because there was hope ahead.

"So, Kara, this "Valhari Poison" really works on slimes, right?"

In the deep forest, a beastman with gray hair, wolf ears, and a tail, a female warrior named Fornelis, asked a woman while walking next to her, shaking the contents of a bottle in her right hand.

The woman in white, who was called Kara, scratched her chestnut hair, which gave her a slightly feeble look...... Fornelis, who called out to her, the princess of this country "Grabalt" which was surrounded by forests. Without replying to the words, she looked around while yawning.

She was looking for a slime.

"I've tested its effectiveness against the slimes in the abandoned mine."

"I've heard, it is unbelievable that a mere liquid like this can dissolve the slime's mucus and expose its weak point, its "nucleus"......"

The word "unbelievable" was used to describe it, and Kara smiled.

"It's not just a liquid, Fornelis-sama, it's tastes like water that has been reversed by the divine power of the goddess Fasalina to become a deadly poison for monster...... It has no negative effects on us humans, though."

"And by the way, it has no smell and no color...... It just looks like water to me. Jenna, are you sure it's safe?"

"Well...... I haven't seen its effects for me to judge, but I trust Kara's knowledge. We'll try it out first―― that's why we're here, right?"

"Well, that's right."

The blonde woman who was walking behind Fornelis―― Jenna, a priestess who was called the "saint", spoke up about their purpose.

There were only three of them here, Kara, Fornelis, and Jenna.

Fornelis was the princess of the country, and Jenna was so famous that she was called the "saint", but no soldiers were protecting them.

The reason for that was to see if the "Valhari Poison" that Kara had made in large quantities was really effective against slime, and because traveling in a large group might attract the slimes.

"Well, if this poison is as effective as Kara says it is, then we can finally fight back."

"Yeah. Right now, only Mariabelle, the mages, and the warriors who are using mithril equipment can fight the slimes... mithril is limited."

"Most of the forest in Grabalt has also been invaded by slimes...... I can't face my ancestors like this."

Jenna chuckled at Fornelis' joking words.

It seemed to be one of the good qualities of this female swordswoman that she could afford to be―― or appear to be mentally relaxed even in such a situation.

Jenna also looked at the clear liquid in the bottle...... the test tube in her hand.

"It neutralizes the slime's mucus and exposes its "nucleus". Then anyone can defeat the slime, not only Mariabelle, a mage, or someone who is using a mithril weapon."

The slime was originally the weakest monster.

A small one could be defeated even by a child―― all they have to do was destroy the small "nucleus" that was its weak point.

It was not strong enough to be broken by a child simply stepping on it with its foot.

However, the slimes that had overrun the continent and occupied Fonteau had various poisons such as paralysis in its bodily fluids, and its volume was so huge that it could swallow a two-story building.

Its combat skills, which have been developed by taking in warriors and knights, have transformed its tentacles into a deadly whip, and even Fornelis, who was now said to be the strongest woman on the continent, felt that she had no chance against multiple slimes.

If there was a poison that could neutralize the mucus that was its weapon and armor, an ordinary soldier could defeat the slime...... That should be a solid counterattacking "weapon".

"Hmm, I found it."

Sniffed*. Fornelis sniffed.

As a beastmen, her sense of smell was far superior to that of a human, and she could easily detect the smell of the slime in the forest.

However, the smell was too thick to tell the exact number, which told the degree of the slime's invasion......

As they stepped in the direction of the odor that Fornelis smelled, if one looked closely, one could see that there was a slime mimicking the cavity of a large tree.

With no concept of time or even emotion, the slime did not even move and had no trouble waiting for people to pass by.

If it had been a human or an elf, they would have walked by without noticing the slime's mimicry and would have been caught by surprise.

The paralyzing poison was so powerful that even a grown man could not move in an instant, and then he would have no choice but to be attacked by the slime without resisting.

Like a hunter, the slime waited patiently for its prey, but it would only make its move when the prey was gathered in one place and there were a small number of them.

They rarely move alone, and Fornelis and the others believed that it was probably a "habit" of theirs.

The slimes have no will or emotion, but they do have instincts.

It killed men and violated women.

It did not change even facing the existence that could kill it―― the "hero" Mariabelle.

Mariabelle had fought the slimes many times, but compared to the male knights who were with her, the attack of the slimes was less frequent.

She wielded the "Sword of the Hero" and the light emitted from its blade made the slime's mucus disappear, but the slimes still tried to "capture" Mariabelle.

The "armor of the hero" neutralized the paralyzing poison of the slime, and the holy sword annihilated the slime with its core.

It was the case even when it came to the hero Mariabelle.

It was clear that there was a kind of instinct as a living organism that ignored its own life, and Kara continued to make use of that instinct to make Mariabelle fight...... even though she understood how much of a burden it would be for the hero's daughter.

This time, she was going to reverse that habit.

The three of them were chosen so that if something unexpected happened, the woman alone would not be killed, and the three of them could deal with multiple slimes.

"Well then, Fornelis-sama. Put the Valhari's poison on the sword."

"Roger that."

As she was told, Fornelis pulled out the iron long sword at her waist, different from her beloved greatsword at her back, and dripped the Valhari's poison on the blade.

As it was, she approached the slime that hid its presence and used mimicry.

――The effect was obvious.

When Fornelis plunged her iron sword, soaked with Valhari's poison, into the slime, the liquid surged, even though it had not destroyed the nucleus, it could no longer maintain its mimicry, and soon even its shape collapsed.

......When the liquid melted into the ground and became a puddle, all that was left was the defenseless "nucleus".

"...It worked."

Fornelis muttered as she shattered the "nucleus" with her iron sword.

Jenna, who was far away from Fornelis, also gasped at the change.

There was still some poison left in the blade, and she thought one could still fight with it a few more times.

"Fufun. How's it going, Jenna-sama, did it work?"

"Y-yes. I didn't expect it to work so quickly......"

"Now everyone will be able to fight the slime. Not just Mariabelle, but everyone."

"Yeah. This will reduce the burden on Mariabelle―― it has been really, really hard for her until today."

Kara and Jenna nodded at Fornelis's words when she returned to them.

As the daughter of the hero and the new hero, Mariabelle was working hard. Standing on the frontlines without rest, wielding her sword, helping her comrades... and that was something only Mariabelle could do, neither her sister Meltia nor Fornelis could replace.

But with the "Valhari Poison", it was different.

One could finally defeat the slime and fight on an equal footing.

The paralyzing poison would be suppressed by the priests' Miracle from the Goddess, and the attack would be a deadly one using the Valhari Poison.

Finally, it was no longer a one-sided battle, but a kill-or-be-killed battle......

The burden on Mariabelle could be reduced...... At that thought from Fornelis, who fought especially on the front lines, unusually loosened her mouth softly and let out a warm sigh.

"Thank you for your hard work, Mariabelle-sama."

"Please stop saying "sama", Fennel-san. It's making me tense."

"I don't think you need to worry so much about it."

The royal castle of Grabalt, the country of beastmen―― a natural fortress built on a part of the world tree that was said to have existed since the time when the goddess Fasalina created the continent.

It was a simple room with wooden furniture and almost no personal belongings.

Her beauty, which was used to be young, had acquired a dignified atmosphere after many battles, and her black hair and dark eyes inherited from her father emphasized her beauty.

Her height had also increased slightly since her time in Fonteau, and her appearance had become more mature, with the word "beautiful" being more appropriate than "pretty girl".

It had been about a year since she was forced to leave her country.

That was enough time for a girl to grow up.

She was dressed in blue armor with black hair and black clothes and had a holy sword hanging from her left hip that purified the air around her.

Mariabelle took off her armor despite the presence of a monster, removed her sword, and loosened the strings of her clothes.

Her white skin peeked out from under her black clothes, and when she loosened her breasts, the strings of her black underwear were visible.

"Are you okay, Fenel-san? Are you being bullied because you're a monster?"

"Hmm~...... I don't really care about that kind of thing, so it's okay. Rather, Kara's been nagging me to go scouting and help her with her luggage."

"Fufu. Fenel-san can fly after all. I think it's easy for Kara to ask you for a favor."

"No. I think she's just forcing trouble on me, that's for sure. She doesn't care if I'm running on fumes or not, she just keeps pushing work on me."

At that lighthearted exchange, Mariabelle's mouth broke down to a smile.

It was a small reprieve from the daily battle.

The fact that a girl who had never even held a sword before had been on the frontlines for the past six months was much heavier and more painful than anyone would have thought.

Her white skin peeking out from the loosened black clothes was uninjured, but the bruises were painful in places.

As a hero, as a hero's daughter...... she was required to be in such a position.

She knew it was coming, but the pressure was more than she could imagine, and she couldn't allow herself to whine.

Was it because she was a monster that she could talk to her without worrying about it, or was it just that she didn't read the mood?

......She was taking care of her in her own way.

Fenelieka told silly stories to Mariabelle, and it had become a routine for her to rest her body in her room like that.

"Why don't you take it a little easier? You'll get tired if you keep going like that."

"I can't do that, there are still a lot of slimes out there."

There was a hint of weariness in her words, and the monster called Fenel...... succubus Fenelieka laid down on the bed with a wry smile.

Her long red hair spread out all over the bed, bouncing in the sunlight that shone through the window, giving the illusion that red flames were spreading across the bed.

Mariabelle picked up some of it.

"Fenel-san's hair is beautiful. I can't even take a bath every day."

"Well, I'm a succubus. I'm good at using magic to clean my body. Do you want me to show you how?"

"Waa, that's convenient."

How long had they been talking like that?

Not that long.

Mariabelle didn't even have enough time to talk about such trivial things, which was why she tried her best to enjoy the idle chit-chat.

......It was over when there were a few light knocks on the door of her room.

"Maria, are you there?"

"Onee-sama? Yes, you can come in."

"I see. Excuse......"

The words were cut off in the middle because the female succubus, not her sister, was lying on the bed in Mariabelle's own room...... where her sister should be resting.

The beautiful woman with a gentle smile twisted her mouth, and with half-closed eyes, she looked at the bed..... where Fenelieka was lying.

"Why are you lying down and resting, Fenelieka?"

"No, she didn't say anything to me."

"......Jeez. You're always getting in the way of Mariabelle's rest."

"I'm not getting in the way. Right, Mariabelle-sama?"

"Fufu. Yeah, I'm fine, onee-sama. I'm resting properly... So what's the matter?"

"Auu……"

It was true that she visited the room because she had some important matters she need to tell Mariabelle, but she also wanted to be angry at the succubus lying in her sister's bed, and the beautiful woman...... who visited her, Mariabelle's sister, Meltia, choked on her words.

In addition to her beautiful silver hair that she inherited from her mother, she wore a large, triangular hat and a thick, fresh-green robe.

In her hand, she was holding a large wooden staff that was also used by her mother, and the large crystal on the tip was glowing faintly in accordance with Meltia's emotions.

Fenelieka smirked at her reaction, which Meltia found annoying.

As she looked at Fenelieka, then at Mariabelle, then at Fenelieka again...... Meltia coughed one more time.

"I've heard Fornelis-sama and the others are talking about heading to Fonteau......?"

“…………”

Mariabelle was at a loss for words as she smiled at her sister's words.

It was a month ago that Kara completed the "Valhari Poison" and distributed it to those who could fight in Grabalt and Lishlua.

It changed the situation on the battlefield, and the burden on Mariabelle was drastically reduced as even ordinary soldiers were able to defeat the slime.

The giant slimes that only she could defeat before have improved to the point where people could now gather and defeat it by taking measures.

That was why they decided to take advantage of the opportunity.

They must use that momentum to retake Fonteau.

It was what Fornelis, Jenna...... and Mariabelle were thinking.

"Yes. Now, the slimes are not yet able to deal with "Valhari poison". If that's the case, it's important that we need to take action and retake the country sooner before they could respond to the poison."

"That's true, but...... but what if this is a trap? What if it's a trap to lure you in, to make you think that they are not ready?"

"It's fine, onee-sama. I have our father's sword and armor...... But the others do not. You're not the only one who has been kidnapped by the slimes."

“…………”

The "miracle of the goddess" used by the priests had limits.

Even those skills that nullified the paralyzing poison were becoming less effective over time, and the slimes know that, so they attack and kidnap women at "the right moment".

It was the same for the daughter of the hero, Mariabelle, the heroes Fornelis and Jenna... they were no exception, and Meltia was kidnapped by the slime.

――They were violated, defiled, and impregnated with a monster child.

It was only about two days since she was violated, but even so, the psychological impact had been so severe that she had rested in Grabalt's castle until today.

"We don't have much time. Even while we are talking about this, many people are being sacrificed...... men and women alike."

At those words, Meltia couldn't say anything.

It was not only the soldiers whose lives were in danger that was being hunted down. Mariabelle was also heartbroken by the danger her comrades were in―― and by the deaths of the soldiers.

Even though she should have known, Meltia swallowed her words as she understood her sister's feelings.

"That's what I'm saying. You care too much, about the slime, about what's going on around you."

"......You don't care too much, though."

The reason why she reflexively responded with strong words instead of being disturbed by Fenelieka's words was probably because they have been doing that kind of exchange on a daily basis.

"Ara, that's terrible. I've helped you so many times already, and you say that to me."

"Uu..."

Meltia averted her gaze at Fenelieka's light-hearted remark.

Meltia, who was an honest woman, was an interesting person to talk to, and if one talked too much to her, she'll respond like a bell.

It was fun to make fun of her, and Meltia would always lose to Fenelieka in this kind of conversation.

And it was not just about conversation, it was also when she was attacked by the slime. The succubus had saved Meltia many times when she was attacked by the slimes every time.

She didn't mind it, but Meltia must feel guilty about it―― and she knew it, which was why she teased her about the topic.

For the succubus, she didn't have much problem about being violated by the slime, the only problem was that it was sticky and disgusting...... That was about it.

However, Meltia was overly concerned about it, and Fenelieka seemed to be amused and fascinated by the seriousness of the sister princess.

......Well, it was like a good toy.

"Fufu. You're too concerned about it, you two. If you're a hero, you should act like a hero and defeat the monsters and save the world...... It was that simple.

If you're too careful around you, you will only wear yourself down... it's weird. "

With a giggle, Fenelieka lay back down on the bed.

"It's fine. It's a good idea to get rid of the slimes as soon as possible. We'll be able to go back to our normal lives."

Fenelieka and the other female succubus were fighting alongside the humans.

The reason for that was because they share a common enemy, the slime.

Once the slime was gone, Fenelieka would disappear from Mariabelle and the others' sight, and they would continue to live their lives as before in human society.

That was everyday life and peace. It was the reason for the hero to fight to regain it.

"Yes, I'll definitely beat it."

"Fufu. I'm looking forward to it, hero-sama."

Even though they were enemies, Fenelieka smiled at Mariabelle.

For a female succubus, these sisters were hard to describe in words―― just interesting.

A hero who was stronger than anyone else but fragile, and a sister who was weak but tried to be strong.

They were cute and interesting. Sisters who were fun to watch.

That was probably why―― even though she was a monster, she was pushing the hero's back.

"Oya, you're very careless to talk while the door is open, Meltia-sama."

"Uge."

However, such a soft smile turned into a look of disgust.

Peeking out from the open door was Kara, a self-proclaimed "scientist" with large black-rimmed glasses, unkempt hair, and a white lab coat.

The female succubus, who had been wearing an air of composure just a moment ago, turned pale at the mere sight of her face.

"What do you mean, "Uge"? It hurts my feelings."

"You're full of shit. You don't have any sense of decency like that."

"Yeah, yeah. Rather than that, Fornelis-sama was looking for you, Mariabelle-sama.

I heard she wanted to talk to you about this month's rounds."

"Ah, I understand."

"Hmmー... sounds like a difficult topic, so I think I'll just stay in this room for a while longer."

"You have another job to do, patrol from the air and distribute the newly formulated "Valhari Poison" to the soldiers."

At Kara's words, Fenelieka's expression visibly clouded.

She had a tired look on her face, unlike the person who had just been acting like a big sister to the sisters.

"......Hey, do you think I'm just a handy little maid, Kara?"

"No way. I think of you as an easy to use and considerate servant."

She said that without any regret, but everyone in the room felt that her tone was somewhat light.

Perhaps something good had happened, they thought.

"Did something good happen, Kara-sama?"

"Yeah. It's rare that not only Fornelis-sama and the others, but also the soldiers praised "Valhari's poison".

I've never been praised like that before."

When Meltia asked, Kara immediately told her what had happened.

What Kara was researching was the power of the Goddess―― a part of the power that summoned heroes from other worlds, which the priests call "miracles".

Although she was from Lishlua, which believed in the goddess, Kara was the first person to investigate the power of the goddess and come up with the idea of using it in medicine and weapons.

However, for those who believed in the goddess for hundreds of years, the mere idea of studying her power was taboo, and Kara's idea was not understood by most people.

The demon king was defeated and the world was about to change...... It was because of the "saint" Jenna, who traveled with the hero and had a certain understanding of science and research.

If the hero hadn't appeared in this world and Jenna hadn't been there, Kara would most likely have been punished heavily as a person who violated the prohibition because of her thoughts.

......However, because of that idea, they were now able to compete with the Black Ooze like this.

"It was forbidden to study the power of the Goddess."

"But it is still necessary, Meltia-sama. So, Fenelieka, help me distribute the Valhari poison now.

Men have a certain amount of cash, and they seem to appreciate it when it is handed to them by a female succubus."

"The poison in that flower smells really bad......"

"That's right for monsters. I'm glad the slime doesn't have a sense of smell, really."

It was ten days before the final battle with the Black Ooze.

The girls, when they were ready, would go to battle against the king of the slimes.

To regain their country.

To save their mother.